Another stupid C question, but be patient with me........

[couch potato]

The one thing I'm having trouble with on C is calling a function. I just don't get how to call a function. I have nothing that explains it.

Like for instance, making a basic calculator. I want a funtion that can add, a function that can multiply, one that can subtract, and one that can divide. I got eveything else down, just not how to call functions . also, do you have to declare functions?

anyone know?

er......Let me re-phrase this: how do you call a funtion in C?

[couch potato]

anyone know?

[couch potato]

no one is answering, so could someone shut down this thread please?

[Martee]

No need to shut the thread down!

To call a function in C, you type the name of the function, followed by parentheses. Within the parentheses, you place any parameters which you are passing to the function.

Suppose we have a function caled MyFunction, which takes no parameters and has a return type of void.

void MyFunction(void)
{
return;
}

To call MyFunction, we simply do the following:
MyFunction();

Suppose that we have a function which takes a few parameters. The function might look something like this
void MyNewFunction(int a, double b)
{
return;
}

When we call this function, we need to pass it parameters. We do this by placing the paramaters between the parentheses:

MyNewFunction(5, 99.99999);


In general, functions must be declared before they are used. So you can either do this:

// Declare the function here
void SomeFunc(void);

int main()
{
// Use it here
SomeFunc();
return 0;
}

// Define it here
void SomeFunc(void)
{
return;
}


or this:


// Declare and define function here
void SomeFunc(void)
{
return;
}

int main()
{
// Use it here
SomeFunc();
return 0;
}

[couch potato]

Thanks for the help

[couch potato]

sorry, im still a little confused. i think i could get it if you could put a small program here that has a couple of basic funtion(s) or one that has just one fuction. so basically, write a small smaple of code using a function. thanks

[Nighthawk]

I think what you're talking about is more of a user interaction question.. Functions (usually called methods) are something that a program does internally. I am guessing you want your calculator program to start, then get some input from the user, then go do its thing.. I know how to do it in VB and in Java, but not in C.

The way to do this would be to have a void main that starts up, then asks the user to "please enter a function" or something like that. Then the user would type in the function, then two numbers, then the program would write out the result, right?

[J-Excel]

Hey Couch Potato, when I tought myself C I picked up a book at my local library. Can't remember which one I got, but I'm sure there are several out there that would help.

[vb6]

A book would definately help heaps .

Perhaps post some code you have written and i sure everyone will be glad to help you out.

I lost all my source codes. Reformated the wrong drive so i can't help much by providing you a live example.

[nukes]

/* Here is a program to show you haw to use functions and pass variables into them, it does not deal with refernecing though. */
#include <stdio.h>
int add_them(a, b)
int main()
  {
    int a, b, c;
    a = 5;
    b = 10;
    c = add_them();
    printf("Result of 5+10 = %d",c);
    return 0;
  }

int add_them(a, b) {
  int a, b, c;
  c = a+b;
  return c; }

How's that? (Probally won't even work )