Point out the error in the program

#include<stdio.h>
int f(in

Point out the error in the program

#include<stdio.h>
int f(int a)
 {
   a > 20? return(10): return(20);
 }
int main()
 {
     int f(int);
     int b;
     b = f(20);
     printf("%d\n", b);
     return 0;
 }

2) There is a error in the below program. Which statement will you add to remove it?

#include<stdio.h>
int main()
 {
     int a;
     a = f(10, 3.14);
     printf("%d\n", a);
     return 0;
 }
 float f(int aa, float bb)
 {
     return ((float)aa + bb);
 }

3) The keyword used to transfer control from a function back to the calling function is

4) What will be the output of the program?

#include<stdio.h>
int main()
 {
     void fun(char*);
     char a[100];
     a[0] = 'A';
 a[1] = 'B';
     a[2] = 'C';
 a[3] = 'D';
     fun(&a[0]);
     return 0;
 }
 void fun(char *a)
 {
     a++;
     printf("%c", *a);
     a++;
     printf("%c", *a);
 }

5) Which of the following is not a library function: