The '%d' is used as format specifier for the integer : printf int « printf scanf « C Tutorial

1. C Tutorial
2. printf scanf
3. printf int

#include <stdio.h>

main(){
    int i,j,k;
   
    i = 6;    
    j = 8;
    k = i + j;
   
    printf("sum of two numbers is %d \n",k);
}

sum of two numbers is 14