This program will input three different numbers & output which is the largest::

#include<conio.h>

#include<stdio.h>

void main()

{clrscr();

int a,b,c;

printf("enter three numbers:\n");

printf(" enter 1st number:");

scanf("%d",&a);

printf("\n enter 2nd number:");

scanf("%d",&b);

printf("\n enter 3rd number:");

scanf("%d",&c);

if(a>b)

{if(a>c)

{printf("\n a is the largest");}

else

{printf("\n c is the largest");}

                                                      }

else

{if(b>c)

{printf("\n b is the largest");}

else

{printf("\n c is the largest");}

                                                     }

getch();}