11.Write a program to generate the Fibonacci series.
Fibonacci series: Any number in the series is obtained by adding the previous two
numbers of the series.
Let f(n) be n'th term.
f(0)=0;
f(1)=1;
f(n)=f(n-1)+f(n-2); (for n>=2)
Series is as follows
011
(1+0)
2 (1+1)
3 (1+2)
5 (2+3)
8 (3+5)
13 (5+8)
21 (8+13)
34 (13+21)
...and so on
Program: to generate Fibonacci Series(10 terms)
#include<stdio.h>
int main() {
//array fib stores numbers of fibonacci series
int i, fib[25];
//initialized first element to 0
fib[0] = 0;
//initialized second element to 1
fib[1] = 1;
//loop to generate ten elements
for (i = 2; i < 10; i++) {
//i'th element of series is equal to the sum of i-1'th element and i-2'th element.
fib[i] = fib[i - 1] + fib[i - 2];
}
printf("The fibonacci series is as follows \n");
//print all numbers in the series
for (i = 0; i < 10; i++) {
printf("%d \n", fib[i]);
}
return 0;
}
Output:
The fibonacci series is as follows
01123581
3
21
34
Explanation:
The first two elements are initialized to 0, 1 respectively. Other elements in the
series are generated by looping
and adding previous two numbes. These numbers are stored in an array and ten
elements of the series are
printed as output.
12.Write a program to print "Hello World" without using semicolon
anywhere in the code.
Generally when we use printf("") statement, we have to use a semicolon at the end.
If printf is used inside an if
condition, semicolon can be avoided.
Program: Program to print some thing with out using semicolon(;)
#include <stdio.h>
int main() {
//printf returns the length of string being printed
if (printf("Hello World\n")) //prints Hello World and returns 11
{
//do nothing
}
return 0;
}
Output:
Hello World
Explanation:
The if statement checks for condition whether the return value of printf("Hello
World") is greater than 0. printf
function returns the length of the string printed. Hence the statement if
(printf("Hello World")) prints the string
"Hello World".
13.Write a program to print a semicolon without using a semicolon anywhere
in the code.
Generally when use printf("") statement we have to use semicolon at the end.
If we want to print a semicolon, we use the statement: printf(";");
In above statement, we are using two semicolons. The task of printing a semicolon
without using semicolon
anywhere in the code can be accomplished by using the ascii value of ' ; ' which is
equal to 59.
Program: Program to print a semicolon without using semicolon in the code.
#include <stdio.h>
int main(void) {
//prints the character with ascii value 59, i.e., semicolon
if (printf("%c\n", 59)) {
//prints semicolon
}
return 0;
}
Output:
;
Explanation:
If statement checks whether return value of printf function is greater than zero or
not. The return value of function
call printf("%c",59) is 1. As printf returns the length of the string printed.
printf("%c",59) prints ascii value that
corresponds to 59, that is semicolon(;).
14.Write a program to compare two strings without using strcmp() function.
strcmp() function compares two strings lexicographically. strcmp is declared in
stdio.h
Case 1: when the strings are equal, it returns zero.
Case 2: when the strings are unequal, it returns the difference between ascii values
of the characters that differ.
a) When string1 is greater than string2, it returns positive value.
b) When string1 is lesser than string2, it returns negative value.
Syntax:
int strcmp (const char *s1, const char *s2);
Program: to compare two strings.
#include<stdio.h>
#include<string.h>
int cmpstr(char s1[10], char s2[10]);
int main() {
char arr1[10] = "Nodalo";
char arr2[10] = "nodalo";
printf(" %d", cmpstr(arr1, arr2));
//cmpstr() is equivalent of strcmp()
return 0;
}/
/s1, s2 are strings to be compared
int cmpstr(char s1[10], char s2[10]) {
//strlen function returns the length of argument string passed
int i = strlen(s1);
int k = strlen(s2);
int bigger;
if (i < k) {
bigger = k;
}
else if (i > k) {
bigger = i;
}
else {
bigger = i;
}
//loops 'bigger' times
for (i = 0; i < bigger; i++) {
//if ascii values of characters s1[i], s2[i] are equal do nothing
if (s1[i] == s2[i]) {
}
//else return the ascii difference
else {
return (s1[i] - s2[i]);
}
}
//return 0 when both strings are same
//This statement is executed only when both strings are equal
return (0);
}
Output:
-32
Explanation:
cmpstr() is a function that illustrates C standard function strcmp(). Strings to be
compared are sent as arguments
to cmpstr().
Each character in string1 is compared to its corresponding character in string2.
Once the loop encounters a
differing character in the strings, it would return the ascii difference of the
differing characters and exit.
15.Write a program to concatenate two strings without using strcat() function.
strcat(string1,string2) is a C standard function declared in the header file string.h
The strcat() function concatenates string2, string1 and returns string1.
Program: Program to concatenate two strings
#include<stdio.h>
#include<string.h>
char *strct(char *c1, char *c2);
char *strct(char *c1, char *c2) {
//strlen function returns length of argument string
int i = strlen(c1);
int k = 0;
//loops until null is encountered and appends string c2 to c1
while (c2[k] != '\0') {
c1[i + k] = c2[k];
k++;
}
return c1;
}
int main() {
char string1[15] = "first";
char string2[15] = "second";
char *finalstr;
printf("Before concatenation:"
" \n string1 = %s \n string2 = %s", string1, string2);
//addresses of string1, string2 are passed to strct()
finalstr = strct(string1, string2);
printf("\nAfter concatenation:");
//prints the contents of string whose address is in finalstr
printf("\n finalstr = %s", finalstr);
//prints the contents of string1
printf("\n string1 = %s", string1);
//prints the contents of string2
printf("\n string2 = %s", string2);
return 0;
}
Output:
Before concatenation:
string1 = first
string2 = second
After concatenation:
finalstr = firstsecond
string1 = firstsecond
string2 = second
Explanation:
string2 is appended at the end of string1 and contents of string2 are unchanged.
In strct() function, using a for loop, all the characters of string 'c2' are copied at the
end of c1. return (c1) is
equivalent to return &c1[0] and it returns the base address of 'c1'. 'finalstr' stores
that address returned by the
function strct().
16.Write a program to delete a specified line from a text file.
In this program, user is asked for a filename he needs to change. User is also asked
for the line number that is
to be deleted. The filename is stored in 'filename'. The file is opened and all the
data is transferred to another file
except that one line the user specifies to delete.
Program: Program to delete a specific line.
#include <stdio.h>
int main() {
FILE *fp1, *fp2;
//consider 40 character string to store filename
char filename[40];
char c;
int del_line, temp = 1;
//asks user for file name
printf("Enter file name: ");
//receives file name from user and stores in 'filename'
scanf("%s", filename);
//open file in read mode
fp1 = fopen(filename, "r");
c = getc(fp1);
//until the last character of file is obtained
while (c != EOF)
{
printf("%c", c);
//print current character and read next character
c = getc(fp1);
}
//rewind
rewind(fp1);
printf(" \n Enter line number of the line to be deleted:");
//accept number from user.
scanf("%d", &del_line);
//open new file in write mode
fp2 = fopen("copy.c", "w");
c = getc(fp1);
while (c != EOF) {
c = getc(fp1);
if (c == '\n')
temp++;
//except the line to be deleted
if (temp != del_line)
{
//copy all lines in file copy.c
putc(c, fp2);
}
}
//close both the files.
fclose(fp1);
fclose(fp2);
//remove original file
remove(filename);
//rename the file copy.c to original name
rename("copy.c", filename);
printf("\n The contents of file after being modified are as follows:\n");
fp1 = fopen(filename, "r");
c = getc(fp1);
while (c != EOF) {
printf("%c", c);
c = getc(fp1);
}
fclose(fp1);
return 0;
}
Output:
Enter file name:abc.txt
hi.
Hello
how are you?
I am fine
hope the same
Enter line number of the line to be deleted:4
The contents of file after being modified are as follows:
hi.
hello
how are you?
hope the same
Explanation:
In this program, user is asked for a filename that needs to be modified. Entered file
name is stored in a char
array 'filename'. This file is opened in read mode using file pointer 'fp1'.
Character 'c' is used to read characters
from the file and print them to the output. User is asked for the line number in the
file to be deleted. The file
pointer is rewinded back and all the lines of the file except for the line to be deleted
are copied into another file
"copy.c". Now "copy.c" is renamed to the original filename. The original file is
opened in read mode and the
modified contents of the file are displayed on the screen.
17.Write a program to replace a specified line in a text file.
Program: Program to replace a specified line in a text file.
#include <stdio.h>
int main(void) {
FILE *fp1, *fp2;
//'filename'is a 40 character string to store filename
char filename[40];
char c;
int del_line, temp = 1;
//asks user for file name
printf("Enter file name: ");
//receives file name from user and stores in 'filename'
scanf("%s", filename);
fp1 = fopen(filename, "r");
//open file in read mode
c = getc(fp1);
//print the contents of file .
while (c != EOF) {
printf("%c", c);
c = getc(fp1);
}
//ask user for line number to be deleted.
printf(" \n Enter line number to be deleted and replaced");
scanf("%d", &del_line);
//take fp1 to start point.
rewind(fp1);
//open copy.c in write mode
fp2 = fopen("copy.c", "w");
c = getc(fp1);
while (c != EOF) {
if (c == '\n') {
temp++;
}
//till the line to be deleted comes,copy the content from one file to other
if (temp != del_line){
putc(c, fp2);
}
else //when the line to be deleted comes
{
while ((c = getc(fp1)) != '\n') {
}
//read and skip the line ask for new text
printf("Enter new text");
//flush the input stream
fflush(stdin);
putc('\n', fp2);
//put '\n' in new file
while ((c = getchar()) != '\n')
putc(c, fp2);
//take the data from user and place it in new file
fputs("\n", fp2);
temp++;
}
//continue this till EOF is encountered
c = getc(fp1);
}
//close both files
fclose(fp1);
fclose(fp2);
//remove original file
remove(filename);
//rename new file with old name opens the file in read mode
rename("copy.c", filename);
fp1 = fopen(filename, "r");
//reads the character from file
c = getc(fp1);
//until last character of file is encountered
while (c != EOF){
printf("%c", c);
//all characters are printed
c = getc(fp1);
}
//close the file pointer
fclose(fp1);
return 0;
}
Output:
Enter file name:abc.txt
hi.
hello
how are you?
hope the same
Enter line number of the line to be deleted and replaced:4
Enter new text: sayonara see you soon
hi.
hello
how are you?
sayonara see you soon
Explanation:
In this program, the user is asked to type the name of the file. The File by name
entered by user is opened in
read mode. The line number of the line to be replaced is asked as input. Next the
data to be replaced is asked. A
new file is opened in write mode named "copy.c". Now the contents of original file
are transferred into new file
and the line to be modified is deleted. New data is stored in its place and remaining
lines of the original file are
also transferred. The copied file with modified contents is replaced with the
original file's name. Both the file
pointers are closed and the original file is again opened in read mode and the
contents of the original file is
printed as output.
18.Write a program to find the number of lines in a text file.
Number of lines in a file can be determined by counting the number of new line
characters present.
Program: Program to count number of lines in a file.
#include <stdio.h>
int main()
/* Ask for a filename and count number of lines in the file*/
{
//a pointer to a FILE structure
FILE *fp;
int no_lines = 0;
//consider 40 character string to store filename
char filename[40], sample_chr;
//asks user for file name
printf("Enter file name: ");
//receives file name from user and stores in a string named 'filename'
scanf("%s", filename);
//open file in read mode
fp = fopen(filename, "r");
//get character from file and store in sample_chr
sample_chr = getc(fp);
while (sample_chr != EOF) {
//Count whenever sample_chr is '\n'(new line) is encountered
if (sample_chr == '\n')
{
//increment variable 'no_lines' by 1
no_lines=no_lines+1;
}
//take next character from file.
sample_chr = getc(fp);
}
fclose(fp); //close file.
printf("There are %d lines in %s \n", no_lines, filename);
return 0;
}
Output:
Enter file name:abc.txt
There are 4 lines in abc.txt
Explanation:
In this program, name of the file to be read is taken as input. A file by the given
name is opened in read-mode
using a File pointer 'fp'. Characters from the file are read into a char
variable 'sample_chr' with the help of getc
function. If a new line character('\n') is encountered, the integer variable 'no_lines'
is incremented. If the
character read into 'sample_char' is not a new line character, next character is read
from the file. This process is
continued until the last character of the file(EOF) is encountered. The file pointer
is then closed and the total
number of lines is shown as output.
19.Write a C program which asks the user for a number between 1 to 9 and
shows the number. If the
user inputs a number out of the specified range, the program should show an
error and prompt
the user for a valid input.
Program: Program for accepting a number in a given range.
#include<stdio.h>
int getnumber();
int main() {
int input = 0;
//call a function to input number from key board
input = getnumber();
//when input is not in the range of 1 to 9,print error message
while (!((input <= 9) && (input >= 1))) {
printf("[ERROR] The number you entered is out of range");
//input another number
input = getnumber();
}
//this function is repeated until a valid input is given by user.
printf("\nThe number you entered is %d", input);
return 0;
}/
/this function returns the number given by user
int getnumber() {
int number;
//asks user for a input in given range
printf("\nEnter a number between 1 to 9 \n");
scanf("%d", &number);
return (number);
}
Output:
Enter a number between 1 to 9
45
[ERROR] The number you entered is out of range
Enter a number between 1 to 9
4
The number you entered is 4
Explanation:
getfunction() function accepts input from user. 'while' loop checks whether the
number falls within range or not
and accordingly either prints the number(If the number falls in desired range) or
shows error message(number is
out of range).
20.Write a program to display the multiplication table of a given number.
Program: Multiplication table of a given number
#include <stdio.h>
int main() {
int num, i = 1;
printf("\n Enter any Number:");
scanf("%d", &num);
printf("Multiplication table of %d: \n", num);
while (i <= 10) {
printf("\n %d x %d = %d", num, i, num * i);
i++;
}
return 0;
}
Output:
Enter any Number:5
5x1=5
5 x 2 = 10
5 x 3 = 15
5 x 4 = 20
5 x 5 = 25
5 x 6 = 30
5 x 7 = 35
5 x 8 = 40
5 x 9 = 45
5 x 10 = 50
Explanation:
We need to multiply the given number (i.e. the number for which we want the
multiplication table)
with value of 'i' which increments from 1 to 10.
Fibonacci series: Any number in the series is obtained by adding the previous two
numbers of the series.
Let f(n) be n'th term.
f(0)=0;
f(1)=1;
f(n)=f(n-1)+f(n-2); (for n>=2)
Series is as follows
011
(1+0)
2 (1+1)
3 (1+2)
5 (2+3)
8 (3+5)
13 (5+8)
21 (8+13)
34 (13+21)
...and so on
Program: to generate Fibonacci Series(10 terms)
#include<stdio.h>
int main() {
//array fib stores numbers of fibonacci series
int i, fib[25];
//initialized first element to 0
fib[0] = 0;
//initialized second element to 1
fib[1] = 1;
//loop to generate ten elements
for (i = 2; i < 10; i++) {
//i'th element of series is equal to the sum of i-1'th element and i-2'th element.
fib[i] = fib[i - 1] + fib[i - 2];
}
printf("The fibonacci series is as follows \n");
//print all numbers in the series
for (i = 0; i < 10; i++) {
printf("%d \n", fib[i]);
}
return 0;
}
Output:
The fibonacci series is as follows
01123581
3
21
34
Explanation:
The first two elements are initialized to 0, 1 respectively. Other elements in the
series are generated by looping
and adding previous two numbes. These numbers are stored in an array and ten
elements of the series are
printed as output.
12.Write a program to print "Hello World" without using semicolon
anywhere in the code.
Generally when we use printf("") statement, we have to use a semicolon at the end.
If printf is used inside an if
condition, semicolon can be avoided.
Program: Program to print some thing with out using semicolon(;)
#include <stdio.h>
int main() {
//printf returns the length of string being printed
if (printf("Hello World\n")) //prints Hello World and returns 11
{
//do nothing
}
return 0;
}
Output:
Hello World
Explanation:
The if statement checks for condition whether the return value of printf("Hello
World") is greater than 0. printf
function returns the length of the string printed. Hence the statement if
(printf("Hello World")) prints the string
"Hello World".
13.Write a program to print a semicolon without using a semicolon anywhere
in the code.
Generally when use printf("") statement we have to use semicolon at the end.
If we want to print a semicolon, we use the statement: printf(";");
In above statement, we are using two semicolons. The task of printing a semicolon
without using semicolon
anywhere in the code can be accomplished by using the ascii value of ' ; ' which is
equal to 59.
Program: Program to print a semicolon without using semicolon in the code.
#include <stdio.h>
int main(void) {
//prints the character with ascii value 59, i.e., semicolon
if (printf("%c\n", 59)) {
//prints semicolon
}
return 0;
}
Output:
;
Explanation:
If statement checks whether return value of printf function is greater than zero or
not. The return value of function
call printf("%c",59) is 1. As printf returns the length of the string printed.
printf("%c",59) prints ascii value that
corresponds to 59, that is semicolon(;).
14.Write a program to compare two strings without using strcmp() function.
strcmp() function compares two strings lexicographically. strcmp is declared in
stdio.h
Case 1: when the strings are equal, it returns zero.
Case 2: when the strings are unequal, it returns the difference between ascii values
of the characters that differ.
a) When string1 is greater than string2, it returns positive value.
b) When string1 is lesser than string2, it returns negative value.
Syntax:
int strcmp (const char *s1, const char *s2);
Program: to compare two strings.
#include<stdio.h>
#include<string.h>
int cmpstr(char s1[10], char s2[10]);
int main() {
char arr1[10] = "Nodalo";
char arr2[10] = "nodalo";
printf(" %d", cmpstr(arr1, arr2));
//cmpstr() is equivalent of strcmp()
return 0;
}/
/s1, s2 are strings to be compared
int cmpstr(char s1[10], char s2[10]) {
//strlen function returns the length of argument string passed
int i = strlen(s1);
int k = strlen(s2);
int bigger;
if (i < k) {
bigger = k;
}
else if (i > k) {
bigger = i;
}
else {
bigger = i;
}
//loops 'bigger' times
for (i = 0; i < bigger; i++) {
//if ascii values of characters s1[i], s2[i] are equal do nothing
if (s1[i] == s2[i]) {
}
//else return the ascii difference
else {
return (s1[i] - s2[i]);
}
}
//return 0 when both strings are same
//This statement is executed only when both strings are equal
return (0);
}
Output:
-32
Explanation:
cmpstr() is a function that illustrates C standard function strcmp(). Strings to be
compared are sent as arguments
to cmpstr().
Each character in string1 is compared to its corresponding character in string2.
Once the loop encounters a
differing character in the strings, it would return the ascii difference of the
differing characters and exit.
15.Write a program to concatenate two strings without using strcat() function.
strcat(string1,string2) is a C standard function declared in the header file string.h
The strcat() function concatenates string2, string1 and returns string1.
Program: Program to concatenate two strings
#include<stdio.h>
#include<string.h>
char *strct(char *c1, char *c2);
char *strct(char *c1, char *c2) {
//strlen function returns length of argument string
int i = strlen(c1);
int k = 0;
//loops until null is encountered and appends string c2 to c1
while (c2[k] != '\0') {
c1[i + k] = c2[k];
k++;
}
return c1;
}
int main() {
char string1[15] = "first";
char string2[15] = "second";
char *finalstr;
printf("Before concatenation:"
" \n string1 = %s \n string2 = %s", string1, string2);
//addresses of string1, string2 are passed to strct()
finalstr = strct(string1, string2);
printf("\nAfter concatenation:");
//prints the contents of string whose address is in finalstr
printf("\n finalstr = %s", finalstr);
//prints the contents of string1
printf("\n string1 = %s", string1);
//prints the contents of string2
printf("\n string2 = %s", string2);
return 0;
}
Output:
Before concatenation:
string1 = first
string2 = second
After concatenation:
finalstr = firstsecond
string1 = firstsecond
string2 = second
Explanation:
string2 is appended at the end of string1 and contents of string2 are unchanged.
In strct() function, using a for loop, all the characters of string 'c2' are copied at the
end of c1. return (c1) is
equivalent to return &c1[0] and it returns the base address of 'c1'. 'finalstr' stores
that address returned by the
function strct().
16.Write a program to delete a specified line from a text file.
In this program, user is asked for a filename he needs to change. User is also asked
for the line number that is
to be deleted. The filename is stored in 'filename'. The file is opened and all the
data is transferred to another file
except that one line the user specifies to delete.
Program: Program to delete a specific line.
#include <stdio.h>
int main() {
FILE *fp1, *fp2;
//consider 40 character string to store filename
char filename[40];
char c;
int del_line, temp = 1;
//asks user for file name
printf("Enter file name: ");
//receives file name from user and stores in 'filename'
scanf("%s", filename);
//open file in read mode
fp1 = fopen(filename, "r");
c = getc(fp1);
//until the last character of file is obtained
while (c != EOF)
{
printf("%c", c);
//print current character and read next character
c = getc(fp1);
}
//rewind
rewind(fp1);
printf(" \n Enter line number of the line to be deleted:");
//accept number from user.
scanf("%d", &del_line);
//open new file in write mode
fp2 = fopen("copy.c", "w");
c = getc(fp1);
while (c != EOF) {
c = getc(fp1);
if (c == '\n')
temp++;
//except the line to be deleted
if (temp != del_line)
{
//copy all lines in file copy.c
putc(c, fp2);
}
}
//close both the files.
fclose(fp1);
fclose(fp2);
//remove original file
remove(filename);
//rename the file copy.c to original name
rename("copy.c", filename);
printf("\n The contents of file after being modified are as follows:\n");
fp1 = fopen(filename, "r");
c = getc(fp1);
while (c != EOF) {
printf("%c", c);
c = getc(fp1);
}
fclose(fp1);
return 0;
}
Output:
Enter file name:abc.txt
hi.
Hello
how are you?
I am fine
hope the same
Enter line number of the line to be deleted:4
The contents of file after being modified are as follows:
hi.
hello
how are you?
hope the same
Explanation:
In this program, user is asked for a filename that needs to be modified. Entered file
name is stored in a char
array 'filename'. This file is opened in read mode using file pointer 'fp1'.
Character 'c' is used to read characters
from the file and print them to the output. User is asked for the line number in the
file to be deleted. The file
pointer is rewinded back and all the lines of the file except for the line to be deleted
are copied into another file
"copy.c". Now "copy.c" is renamed to the original filename. The original file is
opened in read mode and the
modified contents of the file are displayed on the screen.
17.Write a program to replace a specified line in a text file.
Program: Program to replace a specified line in a text file.
#include <stdio.h>
int main(void) {
FILE *fp1, *fp2;
//'filename'is a 40 character string to store filename
char filename[40];
char c;
int del_line, temp = 1;
//asks user for file name
printf("Enter file name: ");
//receives file name from user and stores in 'filename'
scanf("%s", filename);
fp1 = fopen(filename, "r");
//open file in read mode
c = getc(fp1);
//print the contents of file .
while (c != EOF) {
printf("%c", c);
c = getc(fp1);
}
//ask user for line number to be deleted.
printf(" \n Enter line number to be deleted and replaced");
scanf("%d", &del_line);
//take fp1 to start point.
rewind(fp1);
//open copy.c in write mode
fp2 = fopen("copy.c", "w");
c = getc(fp1);
while (c != EOF) {
if (c == '\n') {
temp++;
}
//till the line to be deleted comes,copy the content from one file to other
if (temp != del_line){
putc(c, fp2);
}
else //when the line to be deleted comes
{
while ((c = getc(fp1)) != '\n') {
}
//read and skip the line ask for new text
printf("Enter new text");
//flush the input stream
fflush(stdin);
putc('\n', fp2);
//put '\n' in new file
while ((c = getchar()) != '\n')
putc(c, fp2);
//take the data from user and place it in new file
fputs("\n", fp2);
temp++;
}
//continue this till EOF is encountered
c = getc(fp1);
}
//close both files
fclose(fp1);
fclose(fp2);
//remove original file
remove(filename);
//rename new file with old name opens the file in read mode
rename("copy.c", filename);
fp1 = fopen(filename, "r");
//reads the character from file
c = getc(fp1);
//until last character of file is encountered
while (c != EOF){
printf("%c", c);
//all characters are printed
c = getc(fp1);
}
//close the file pointer
fclose(fp1);
return 0;
}
Output:
Enter file name:abc.txt
hi.
hello
how are you?
hope the same
Enter line number of the line to be deleted and replaced:4
Enter new text: sayonara see you soon
hi.
hello
how are you?
sayonara see you soon
Explanation:
In this program, the user is asked to type the name of the file. The File by name
entered by user is opened in
read mode. The line number of the line to be replaced is asked as input. Next the
data to be replaced is asked. A
new file is opened in write mode named "copy.c". Now the contents of original file
are transferred into new file
and the line to be modified is deleted. New data is stored in its place and remaining
lines of the original file are
also transferred. The copied file with modified contents is replaced with the
original file's name. Both the file
pointers are closed and the original file is again opened in read mode and the
contents of the original file is
printed as output.
18.Write a program to find the number of lines in a text file.
Number of lines in a file can be determined by counting the number of new line
characters present.
Program: Program to count number of lines in a file.
#include <stdio.h>
int main()
/* Ask for a filename and count number of lines in the file*/
{
//a pointer to a FILE structure
FILE *fp;
int no_lines = 0;
//consider 40 character string to store filename
char filename[40], sample_chr;
//asks user for file name
printf("Enter file name: ");
//receives file name from user and stores in a string named 'filename'
scanf("%s", filename);
//open file in read mode
fp = fopen(filename, "r");
//get character from file and store in sample_chr
sample_chr = getc(fp);
while (sample_chr != EOF) {
//Count whenever sample_chr is '\n'(new line) is encountered
if (sample_chr == '\n')
{
//increment variable 'no_lines' by 1
no_lines=no_lines+1;
}
//take next character from file.
sample_chr = getc(fp);
}
fclose(fp); //close file.
printf("There are %d lines in %s \n", no_lines, filename);
return 0;
}
Output:
Enter file name:abc.txt
There are 4 lines in abc.txt
Explanation:
In this program, name of the file to be read is taken as input. A file by the given
name is opened in read-mode
using a File pointer 'fp'. Characters from the file are read into a char
variable 'sample_chr' with the help of getc
function. If a new line character('\n') is encountered, the integer variable 'no_lines'
is incremented. If the
character read into 'sample_char' is not a new line character, next character is read
from the file. This process is
continued until the last character of the file(EOF) is encountered. The file pointer
is then closed and the total
number of lines is shown as output.
19.Write a C program which asks the user for a number between 1 to 9 and
shows the number. If the
user inputs a number out of the specified range, the program should show an
error and prompt
the user for a valid input.
Program: Program for accepting a number in a given range.
#include<stdio.h>
int getnumber();
int main() {
int input = 0;
//call a function to input number from key board
input = getnumber();
//when input is not in the range of 1 to 9,print error message
while (!((input <= 9) && (input >= 1))) {
printf("[ERROR] The number you entered is out of range");
//input another number
input = getnumber();
}
//this function is repeated until a valid input is given by user.
printf("\nThe number you entered is %d", input);
return 0;
}/
/this function returns the number given by user
int getnumber() {
int number;
//asks user for a input in given range
printf("\nEnter a number between 1 to 9 \n");
scanf("%d", &number);
return (number);
}
Output:
Enter a number between 1 to 9
45
[ERROR] The number you entered is out of range
Enter a number between 1 to 9
4
The number you entered is 4
Explanation:
getfunction() function accepts input from user. 'while' loop checks whether the
number falls within range or not
and accordingly either prints the number(If the number falls in desired range) or
shows error message(number is
out of range).
20.Write a program to display the multiplication table of a given number.
Program: Multiplication table of a given number
#include <stdio.h>
int main() {
int num, i = 1;
printf("\n Enter any Number:");
scanf("%d", &num);
printf("Multiplication table of %d: \n", num);
while (i <= 10) {
printf("\n %d x %d = %d", num, i, num * i);
i++;
}
return 0;
}
Output:
Enter any Number:5
5x1=5
5 x 2 = 10
5 x 3 = 15
5 x 4 = 20
5 x 5 = 25
5 x 6 = 30
5 x 7 = 35
5 x 8 = 40
5 x 9 = 45
5 x 10 = 50
Explanation:
We need to multiply the given number (i.e. the number for which we want the
multiplication table)
with value of 'i' which increments from 1 to 10.
