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) Which of the following is not a library function:

3) 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;
 }

4) What will be the output of the program?

#include<stdio.h>
int main()
 {
     int fun(int);
     int i = fun(10);
     printf("%d\n", --i);
     return 0;
 }
int fun(int i)
 {
    return (i++);
 }

5) How many times the program will print "Study 2 Online" ?

  #include<stdio.h>
  int main()
 {
     printf("Study 2 Online");
     main();
     return 0;
 }