I am writing a calculator program in C. I need a function definition for a function called Subtract() that will allow me to calculate the difference of several numbers entered by the user also need one for division

That's not so hard.. Have you tried anything yet? Have you learned about functions? Example:

int Substract(int x, int y)
{
    //do something with x and y
    return answer;
}

Niek

Not that easy, I guess you need to parse a complex expression like a+b-c*d and evaluate, you need to learn about binary search tree, and about postorder traversal ,etc.

Not that easy, I guess you need to parse a complex expression like a+b-c*d and evaluate, you need to learn about binary search tree, and about postorder traversal ,etc.

Hey thanks I figured it wouldnt be easy.

Not that easy, I guess you need to parse a complex expression like a+b-c*d and evaluate, you need to learn about binary search tree, and about postorder traversal ,etc.

Not necessarily. If it's just a simple calculator program (as the original poster seems to be implying), then the program itself will likely be no more complex than a simple pocket calculator. Remember, a program only has to be as complex as the requirements state.