syntax errors

Hello,
I'm having a problem with with code. Here is my code

Code:

#include <stdio.h>
#include <iostream>
#include namespace std

main()
{
	int *num1;
	int *num2;
	int *op;

	num1 = new int;
	num2 = new int;
	op = new int;

	cout<<"Enter first number:"; 	//error: 'cout' was not declared in scope
	cin>> *num1;			//error: 'cin' was not declared in scope

	cout<<"Enter second number:";
	cin>> *num2;

	while(*op != 6)
	{
		cout<<"1: Addition"
	    	    <<"2: Subtraction"
	    	    <<"3: Multiplication"
	    	    <<"4: Division"
	    	    <<"5: Modulus"
	    	    <<"6: Exit\n"
	    	    <<"Please enter a choice:";
		cin<< *op;

		switch(*op)
		{
			case (1):
				cout<< *num1 + *num2;
				break;
			case (2):
				cout<< *num1 + *num2;
				break;
			case (3):
				cout<< (*num1) * (*num2);
				break;
			case (4):
				if(*num2 == 0)
					cout<<"Unable to perform division."
				    	    << " Please enter a nonzero second number";
				else
					cout<< (*num1) / (*num2);
					break;
			case (5):
				cout<< (*num1) % (*num2);
				break;
			case (6):
				break;
			default:
				cout<< "Please enter valid option";
				break;
		}
	}

}

when compiling i would get these errors

calculator.cpp: In function `int main()':
calculator.cpp:30: error: no match for 'operator<<' in 'std::cin << *op'

line 30 being

Code:

cin<< *op;

any idea on what could cause this? I'm new to c++, please bare with me.

Code:

	while(*op != 6)
	{
		cout<<"1: Addition"
	    	    <<"2: Subtraction"
	    	    <<"3: Multiplication"
	    	    <<"4: Division"
	    	    <<"5: Modulus"
	    	    <<"6: Exit\n"
	    	    <<"Please enter a choice:";
		cin<< *op;

CommonTater has pointed out the source of the error, but actually you could have found it yourself quite easily because your compiler provided the line number (30) in the error message.

Besides this, you failed to match new with delete, but you don't need them here, so why use them?

can you show me an example of delete? do I always need to delete when an anonymous variable is looped?

Originally Posted by aromash

can you show me an example of delete?

You should have learnt it when you learnt to use new. My point is that you could have written:

Code:

int num1;
int num2;
int op;

cout << "Enter first number:";
cin >> num1;

cout << "Enter second number:";
cin >> num2;

Now you do not need delete.

Also the line

Code:

#include namespace std

should be

Code:

using namespace std;

Jim

While we're at it:

- You should not declare main without return type. It is either int main() or int main(int argc, char** argv) or nothing.
- You should use <cstdio> when using that header, but you are not even using it so you can just remove it.
- Parentheses are not necessary in the case statements.
- In the line displaying the menu you do not need the << operator on each line. You can simply finish that line with an \ and continue the text on the other line.

All of these problems could be avoided if you just selected a free IDE that offered syntax highlighting.........

Originally Posted by Alexandre

- You should not declare main without return type. It is either int main() or int main(int argc, char** argv) or nothing.

This one is puzzling. Because the standard mandates that all function must have a return type, this code should not compile. Not to mention #include namespace std probably wouldn't compile very well or spot out a lot of warnings.
So that begs the question: what compiler/IDE are you using?