C++ :: Asterisk Bar Graph

i have to make a programs that prompts the user to enter quiz grades and add them up. For examples the user enters 6 test grades they are out of 5 so he enters 0-5 and i store them in the array. This part works great but now i have to print out a bar of vertical asterisks for every part too. So if at the end we have one test grades that are 2 grades of 1 points, 1 grade of two point, 2 grades of three point and 1 grade of 5 point it will have to display them as this

There are 2 grades of 1
There are 1 grades of 2
There are 2 grades of 3
There are 1 grades of 5

i need to do for loops but i am stuck on what to count too and what to print i know i will need cout << "*" and a couple of spaces.

#include <iostream>
using namespace std;
int main (){
int size;
int tests;
int a[6]={0};

cout << "How many quiz scores will you enter: ";
cin >> size;

[code]....