C Programming - Library Functions
- Library Functions - General Questions
- Library Functions - Find Output of Program
- Library Functions - Point Out Errors
- Library Functions - True / False Questions
- Library Functions - Yes / No Questions
#include<stdio.h>
int main()
{
int i;
i = printf("How r u\n");
i = printf("%d\n", i);
printf("%d\n", i);
return 0;
}
i = printf("How r u\n");
This line prints "How r u" with a new line character and returns the length of string printed then assign it to variable i.
So i = 8 (length of '\n' is 1).
i = printf("%d\n", i); In the previous step the value of i is 8. So it prints "8" with a new line character and returns the length of string printed then assign it to variable i. So i = 2 (length of '\n' is 1).
printf("%d\n", i); In the previous step the value of i is 2. So it prints "2".
#include<stdio.h>
#include<math.h>
int main()
{
float i = 2.5;
printf("%f, %d", floor(i), ceil(i));
return 0;
}
Both ceil() and floor() return the integer found as a double.
floor(2.5) returns the largest integral value(round down) that is not greater than 2.5. So output is 2.000000.
ceil(2.5) returns 3, while converting the double to int it returns '0'.
So, the output is '2.000000, 0'.
#include<stdio.h>
int main()
{
int i;
i = scanf("%d %d", &i, &i);
printf("%d\n", i);
return 0;
}
i = scanf("%d %d", &i, &i); Here Scanf() returns 2. So i = 2.
printf("%d\n", i); Here it prints 2.
#include<stdio.h>
int main()
{
int i;
char c;
for(i=1; i<=5; i++)
{
scanf("%c", &c); /* given input is 'b' */
ungetc(c, stdout);
printf("%c", c);
ungetc(c, stdin);
}
return 0;
}
The ungetc() function pushes the character c back onto the named input stream, which must be open for reading.
This character will be returned on the next call to getc or fread for that stream.
One character can be pushed back in all situations.
A second call to ungetc without a call to getc will force the previous character to be forgotten.
#include<stdio.h>
#include<stdlib.h>
int main()
{
char *i = "55.555";
int result1 = 10;
float result2 = 11.111;
result1 = result1+atoi(i);
result2 = result2+atof(i);
printf("%d, %f", result1, result2);
return 0;
}
Function atoi() converts the string to integer.
Function atof() converts the string to float.
result1 = result1+atoi(i);
Here result1 = 10 + atoi(55.555);
result1 = 10 + 55;
result1 = 65;
result2 = result2+atof(i);
Here result2 = 11.111 + atof(55.555);
result2 = 11.111 + 55.555000;
result2 = 66.666000;
So the output is "65, 66.666000" .