HELP! How to use a loop to ask for 5 grades?

[sam89m]

I am only one week into programming, and I am wondering how I can turn the test scores into a for loop (instead of asking 5 times)?

#include <iostream>
#include <cmath>
using namespace std;

int main () 
{

double project_1,test_1,test_2,test_3,test_4,test_5,overall_grade;

cout << "Please enter project_1 grade\n";
cin >> project_1;

cout << "Please enter test_1 grade\n";
cin >> test_1;
cout << "Please enter test_2 grade\n";
cin >> test_2;
cout << "Please enter test_3 grade\n";
cin >> test_3;
cout << "Please enter test_4 grade\n";
cin >> test_4;
cout << "Please enter test_5 grade\n";
cin >> test_5;

overall_grade = ((((test_1 + test_2 + test_3 + test_4 + test_5)/5)* 0.5) + (project_1 * 0.5))

cout << "Your grade is\n";
cout << overall_grade;

return 0;

}

[MiiNiPaa]

USe arrays and loops:

#include <iostream>

int main ()
{
    const int TESTS = 5;
    double project;
    double test[TESTS];

    std::cout << "Please enter project_1 grade\n";
    std::cin >> project;

    double overall_grade = 0;
    for(int i = 0; i < TESTS; ++i) {
        std::cout << "Please enter test " << i + 1 << " grade\n";
        std::cin >> test[i];
        overall_grade += test[i];
    }
    overall_grade = overall_grade / 5 * 0.5  +  project * 0.5;
    std::cout << "Your grade is\n" << overall_grade;
}

[sam89m]

Thanks for your help!

[Zaita]

#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

int main ()
{
    const unsigned TESTS = 5;
    double project;
    double test[TESTS];

    std::cout << "Please enter project_1 grade\n";
    std::cin >> project;

    double overall_grade = 0;
    for(unsigned i = 0; i < TESTS; ++i) {
        std::cout << "Please enter test " << i + 1 << " grade\n";
        std::cin >> test[i];
        overall_grade += test[i];
    }
    overall_grade = overall_grade / 5 * 0.5  +  project * 0.5;
    std::cout << "Your grade is\n" << overall_grade;

    return 0;
}

You should used unsigned instead of int when it can/will never be negative.
You should always return 0 from main.

This compiles fine on GCC 4.8 and 4.9.

I'd also note that using cin >> test[i] is horrible as it won't handle any invalid input correctly. Look at using std::getline() and doing type conversions with stringstream or boost::lexical_cast<>()