functions

[moot1]

Im trying to learn multiple functions and trying to put a class in a program. Cans you please tell me what bit of code to make into a function to call into main to make the program shorter and what to put in a class

#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
    int Total = 0;
	int Amount;
	int Number;
	int whatoperation;
	int answertoaverage;
	int restart;

	while (restart) {
    system("CLS");

	cout << "Here are your choices(enter the number before the operation)" << endl << endl;
	cout << "1.Addition" << endl;
	cout << "2.Subtraction" << endl;
	cout << "3.Multiplication" << endl;
	cout << "4.Division" << endl;
	cout << "5.Average Calculator" << endl;

	cin >> whatoperation;

	system("CLS");

	switch(whatoperation){
    case 1:
    cout << "Enter in how many numbers you want to use" << endl;
	cin >> Amount;

	for(int i = 0; i < Amount; i++)   // Keeps looping until i == Amount
	{
		cout << "Number " << i << ": " ;  // Shows user what number they are entering
		cin >> Number;

		Total = Number + Total;  // Adds number to total
	}

	cout << "The total is " << Total << endl;  // Prints out total value when loop has finished
	break;

	case 2:
	cout << "Enter in how many numbers you want to use" << endl;
	cin >> Amount;

	for(int i = 0; i < Amount; i++)
	{
		cout << "Number " << i << ": " ;
		cin >> Number;

		if(i == 0)
		{
			Total = Total + Number;
		}

		else
		{
			Total = Total - Number;
		}
	}

	cout << "The total is " << Total << endl;
	break;

	case 3:
	cout << "Enter in how many numbers you want to use" << endl;
	cin >> Amount;

	for(int i = 0; i < Amount; i++)
	{
		cout << "Number " << i << ": " ;
		cin >> Number;

		if(i == 0)
		{
			Total = Total + Number;
		}

		else
		{
			Total = Total * Number;
		}
	}
	cout << "The total is " << Total << endl;
	break;

	case 4:
	cout << "Enter in how many numbers you want to use" << endl;
	cin >> Amount;

	for(int i = 0; i < Amount; i++)
	{
		cout << "Number " << i << ": " ;
		cin >> Number;

		if(i == 0)
		{
			Total = Total + Number;
		}

		else
		{
			Total = Total / Number;
		}
		cout << "The total is " << Total << endl;
	}
	break;
	case 5:
	cout << "Enter how many numbers you want to find the average of: ";
	cin >> Amount;

	for(int i = 0; i < Amount; i++)
	{
	    cout << "Number " << i << ": " ;
		cin >> Number;

		Total = Number + Total;
	}
	answertoaverage = Total / Amount;
	cout << "The average of those " << Amount << " numbers is " << answertoaverage << endl;
}
	cout << "enter 1 to restart or 2 to quit: ";
	cin >> restart;
	if(restart == 1){
    }else{
        break;
    }

    }

    cin.get();
	return 0;
}

[moot1]

can some one please answer

[clanmjc]

Create a function for each of your case statements and have that function perform what that case intends it to do.

case 1: doSomething(); break;
case 2: doSomthingElse(); break;
case 3: doSomethingCrazy(); break;
case 4: doSomethingForever(); break;

And go from there.

[eyesofhope]

Going from what the last person said, you can create a function (like int main) by either making an int function, which holds a value, something you want to output(which would be very helpful in this program) or a void function.

for example:

#include <iostream>
using namespace.std

int somefunction()
{
    //addition
}
int anotherfunction()
{
  //subtraction, etc...
}
int main()
{
//blah blah
case 1:
somefunction(); //calls whatever that function does, in this case the comment of addition does    nothing, to do it here
break;
case 2:
anotherfunction(); //calls the function anotherfunction to work here
break;
}

The void function is the same but cannot hold a value:

void somefunction()
{
//whatever it does
}
int main()
{
somefunction(); //calls the function above to use right here
}

Keep in mind that the parentheses behind the function can retain a value or variable.
hope that helps!

[WhiteWind]

        int someFunc()
        {
            int x = 1;
            return x; // This is okay, function type is int, it's returning an int
        }
        
        double someFunc()
        {
            float x = 1.2;
            return x; // ERROR, can only return type double
        }
        
        void someFunc()
        {
            int x = 1;
            return x; // ERROR, can't return anything (void function)
        }

They can all take and arguments though:

        int someFunc(char a, int b, int c)
        double someFunc(int a, double b)
        void someFunc(string a, float b, float c, int d)

[LB]

        double someFunc()
        {
            float x = 1.2;
            return x; // ERROR, can only return type double
        }

Uh, no, this is completely valid. A float is always implicitly convertible to a double, because a double is more precise than a float and can take its value. This is an 'implicit widening cast'

[WhiteWind]

Oh yeah.. just like you can return a double in an int function (even though you'd lose the precision). Or did I get that backwards?

[LB]

You would not lose precision ;p

Also, what is a 'double function' or a 'void function'? I do not understand, there are only functions, and some can return values while others return nothing.

[WhiteWind]

I mean their return type (double function(), void function()).

[LB]

Oh, I was confused.

double Func1(); //Function which returns a double
void Func2();   //Function which returns nothing 

:)