tabla de multiplicación usando c

#include <stdio.h>

int main(){
	//declaring variables
    int n,i,a,start,end;
    //taking and printing the instructions
    printf("Enter first number from where you want to start multiplication : \n");
    scanf("%d",&start);
     printf("Enter Last number from where you want to end multiplication : \n");
    scanf("%d",&end);
  	//using loops

    for(n=start;n<=end;n++){
        a=0;
        for(i=1;i<=10;i++){
            a+=n; //setting the value of a. i used addition instead of multiplication
          //because computer takes too much time for multiplating numbers than doing addition
          
            printf("%d x %d = %d\n",n,i,a);

        }
        printf("Multiplication has ended of %d\n\n",n);
    }


    return 0;


}
rifatibn