Need help in C++ (Basic stuff)

[Moskis]

Hey I am coding a simple calculator at the moment in C++. I would love some help with.
I am coding in console and I wrote this to start with:
cout << "Would you like to calculate PLUS or MINUS? \n";
Now I want to do so if they would write plus it would do + and else -

I am a total noob since I started today and this is how my code looks like (it does not work)

#include <iostream>
using namespace std;

int main()
{
	int a;
	int b;
	int sum;
	int sum2;
	
	cout << "Would you like to calculate PLUS or MINUS? \n";
* * *   char input = cin.get();

	if(input == 'plus')
	{
	cout << "Enter a number! \n";
	cin >> a;

	cout << "Enter another number! \n";
	cin >> b;

	sum = a + b;
	cout << "The sum of those numbers is " << sum << endl;
	}
	else
{
	cout << "Enter a number! \n";
	cin >> a;

	cout << "Enter another number! \n";
	cin >> b;

	sum2 = a - b;
}
	return 0;
}

[l0l1dk]

Hey I am coding a simple calculator at the moment in C++. I would love some help with.
I am coding in console and I wrote this to start with:
cout << "Would you like to calculate PLUS or MINUS? \n";
Now I want to do so if they would write plus it would do + and else -

I am a total noob since I started today and this is how my code looks like (it does not work)

#include <iostream>
using namespace std;

int main()
{
	int a;
	int b;
	int sum;
	int sum2;
	
	cout << "Would you like to calculate PLUS or MINUS? \n";
* * *   char input = cin.get();

	if(input == 'plus')
	{
	cout << "Enter a number! \n";
	cin >> a;

	cout << "Enter another number! \n";
	cin >> b;

	sum = a + b;
	cout << "The sum of those numbers is " << sum << endl;
	}
	else
{
	cout << "Enter a number! \n";
	cin >> a;

	cout << "Enter another number! \n";
	cin >> b;

	sum2 = a - b;
}
	return 0;
}

Try if(strcmp(input, "plus") == 0) instead of if(input == 'plus'). C strings (char*s) can't be reliably compared using ==.

Also, you forgot to print out the result of the subtraction.

[Moskis]

Yea I know I added that :P However I found out that if I change if(input =='plus') to if(input == 'hello') or whatever (anything but plus) it works. Something makes it screw up if I type minus or plus into the cmd... Why's that? :S

EDIT: Also with if(strcmp(input, "plus") == 0) I get

'input' : undeclared identifier

[l0l1dk]

Yea I know I added that :P However I found out that if I change if(input =='plus') to if(input == 'hello') or whatever (anything but plus) it works. Something makes it screw up if I type minus or plus into the cmd... Why's that? :S

Change char input = cin.get(); to char input[25];
ZeroMemory(input, 25);
cin >> input;

And use " instead of '.

[Moskis]

Change char input = cin.get(); to char input[25];
ZeroMemory(input, 25);
cin >> input;

And use " instead of '.

Oh. Now ZeroMemory is undefined... :/

edit: got it working without the "ZeroMemory(input, 25);" part
and why the number 25? ASCII I suppose?

[l0l1dk]

Oh. Now ZeroMemory is undefined... :/

Add #include to the start of the file.

EDIT: The 25 means that the string has a maximum length of 24 characters (+ the null character).

[Moskis]

Add #include <Windows.h> to the start of the file.

What does that even do? It seems to work without it.

Also +4 for you!

[l0l1dk]

What does that even do? It seems to work without it.

Also +4 for you!

Windows.h holds the function declarations for the Windows API. ZeroMemory is a macro used by the Windows API, and it's in Windows.h.

[Moskis]

Windows.h holds the function declarations for the Windows API. ZeroMemory is a macro used by the Windows API, and it's in Windows.h.

I meant the ZeroMemory thing. The calculator works now without it.

[l0l1dk]

I meant the ZeroMemory thing. The calculator works now without it.

The ZeroMemory would've set the string to have no value. Sometimes variables will have random values when they're allocated unless they're initialized with a value. This can sometimes cause problems, so the ZeroMemory sets the string to have no value instead of a possibly random one.

[Moskis]

The ZeroMemory would've set the string to have no value. Sometimes variables will have random values when they're allocated unless they're initialized with a value. This can sometimes cause problems, so the ZeroMemory sets the string to have no value instead of a possibly random one.

Thank you very much good sir!

[DarkLinux]

Just use GetAsyncKeyState(VK_xxx)

[mahdiciaco]

check this:C++ Tutorial - Learn C++ - Cprogramming.com