warning c4700

This is a discussion on warning c4700 within the C++ Programming forums, part of the General Programming Boards category; learning functions and I am having trouble with some local variables. I keep getting "warning C4700: uninitialized local variable 'y' ...

  1. #1
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    warning c4700

    learning functions and I am having trouble with some local variables. I keep getting "warning C4700: uninitialized local variable 'y' used", same for the variable x. Are my loops in combinations with cin >> messing up the code? I am pretty new to programming, any help would be greatly appreciated. Heres the code:

    Code:
    #include <iostream>
    using namespace std;
    
    //function prototype
    double calculateRetail(double, double);
    
    int main()
    {
    	double x, y, z;
    	
    	while(x < 0)
    	{
    		cout << "This progam calculates and displays an items retail price. Enter the whole sale price...\n";
    		cin >> x;
    	}
    
    	while(y < 0)
    	{
    		cout << "Enter the markup percentage...\n";
    		cin >> y;
    	}
    
    
    	z = calculateRetail(x, y);
    	cout << z << " is the retail price.\n";
    	return 0;
    }
    	
    double calculateRetail(double x, double y)
    {
    	return x * y * .01;
    }

  2. #2
    C++ Witch laserlight's Avatar
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    As the message says, you compare x < 0 and y < 0 before initialising x and y with some value. Perhaps a do while loop is what you want, but note that you are assuming that the user enters integral input.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
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    Thank you. The Do-while loop worked perfectly, I also had my math wrong lol =).

    Anyways, heres what the code is now.

    Code:
    #include <iostream>
    using namespace std;
    
    //function prototype
    double calculateRetail(double, double);
    
    int main()
    {
    	double x, y, z;
    	
    	do
    	{
    		cout << "This progam calculates and displays an items retail price. Enter the whole sale price...\n";
    		cin >> x;
    	}while(x < 0);
    
    	do
    	{
    		cout << "Enter the markup percentage...\n";
    		cin >> y;
    	}while(y < 0);
    
    
    	z = calculateRetail(x, y);
    	cout << z << " is the retail price.\n";
    	return 0;
    }
    	
    double calculateRetail(double x, double y)
    {
    	return x * (y + 100) * .01;
    }

  4. #4
    C++ Witch laserlight's Avatar
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    Incidentally, instead of naming your variables x, y and z, use descriptive names like whole_sale_price, markup_percentage, and retail_price.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  5. #5
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    Thank you for the tip, I will make sure to do that in the future =)

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