Adding two Numbers

#include <stdio.h>

int main(void)
{
 int n, m;

 printf("Please enter two Numbers: "); //be sure to click space between the two numbers
 scanf("%i %i", &n, &m);

 printf("Adding both Numbers......\n");
 printf("Sum= %i\n", n+m);

 return 0;
}

Printing defined Number

#include <stdio.h>
int main(void)
{
 int n=9;
 printf("Number: %i\n", n);

 return 0;
}

Hello World

#include <stdio.h>

int main(void)
{
 printf("Hello World!\n");

 return 0;
}