The keyword used to transfer control from a function back to the calling functio

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

2) 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);
 }

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()
 {
     int i=1;
     if(!i)
         printf("Study2Online,");
     else
     {
         i=0;
         printf("C-Program");
         main();
     }
     return 0;
 }

5) What will be the output of the program?

#include<stdio.h>
void fun(int);
typedef int (*pf) (int, int);
int proc(pf, int, int);
int main()
 {
     int a=3;
     fun(a);
     return 0;
 }
void fun(int n)
 {
     if(n > 0)
     {
         fun(--n);
         printf("%d,", n);
         fun(--n);
     }
 }