C/C++ :: Sum Function Of For Loop For Dice Generator

I have written the code below that allows the user to input any sided dice and any number of rolls. The program will print out the output in sequence. I need to sum these outputs into one number, but I am having trouble writing a sum function for this.

//This Program Creates the Sum of a Number of Dice Rolls of the Same Size  

#include <stdio.h> 
#include <math.h>
#include <time.h> 
int rolldie();   
int main(){ 
int x, n, a; //'x' n=number of rolls, a=number sided dice

[Code] ....

The output looks something like this currently:

Please Enter the Number Sided Dice Followed by the number of Rolls... 12 10
4 12 2 10 12 5 5 12 12 5 >Exit code: 0