Question

I am not familiar to Eclipse IDE. I want to know how can O call various functions from a single source file that contains a main() function.

For Example

Project name – TestProject
Source File name – EntryPoint.c

Now I want to make various method like add(), Sub(), mul() etc.

Please tell me these method should be in another source file or a file.

Answer 1

If you want to call a function that is defined in another source file, you still need to declare the function in the source file you are calling it from. This is commonly done through the use of header files which are included at the top of each source file that refers to the function.

Here is an example.

methods.c

#include "header.h"

int add(int a, int b){
    return a+b;
}
int sub(int a, int b){
    return a-b;
}
int mult(int a, int b){
    return a*b;
}

EntryPoint.c

#include "header.h"

int main(){
    return sub(add(2, 3), mult(2,5));
}

header.h

#ifndef _HEADER_H
#define _HEADER_H

int add(int, int);
int sub(int, int);
int mult(int, int);

#endif