Program for calculating the average of students and displaying failed classes

#include <iostream>
using namespace std;
int main()
{
    int grades[50][10], s, c;
    cout << "Number of students: "<<endl;
    cin >> s;
    cout << "Number of classes the students took: "<<endl;
    cin >> c;
    for (int i = 0; i < s;i++) { //loop for entering grades
        cout << "Enter the grades for student "<<i+1<<": "<<endl;
        for (int j = 0; j < c;j++) {
            cin >> grades[i][j];
        }
    }
    for (int i = 0; i < s;i++) { //loop for displaying grades
        float sum = 0.0;
        int counter=0;
        for (int j = 0; j < c;j++) {
            if (grades[i][j] == 2) {
                counter++;
            }
            else {
                sum = sum + grades[i][j];
            }
        }
        if (counter>0) {
            cout << "Student "<<i+1<<" has failled "<<counter<<" classes!"<<endl;
        }
        else {
            cout << "Student " << i + 1 <<" has an average of "<<sum/c<<"." << endl;
        }
    }
}