C code for calling other APIs in C and displaying them

I have to write a program in C, where there would be list of options.
like
1
2
3
4
5

now by pressing 1 i would be able to call the API of C program already written and able to display in screen.
and so on by pressing 2, 3, 4 ,5

I am new to C and don’t have experience in writing C codes.

Pls explain me with a simple program hw to do that.

thanks in advance

Hello Ashutosh
May be this program will help you…
#include"stdio.h"
#include"conio.h"
#include"stdlib.h"
void main()

{

int n;

while(1)

{

  clrscr();
  printf("Here is your options...\n");
  printf("1.op1\n2.op2\n3.op3\n4.EXIT\n");
  scanf("%d",&n);
  switch(n)
  {
     case 1: printf("this is op1\n");
             /* in these cases you can write code of your choice. */
             break;
     case 2:  printf("this is op2\n");
              break;
     case 3:  printf("this is op3\n");
              break;
     case 4:  exit(1);
   }
}
getch();

}

//