Functions

This example is on functions. With Functions you need to state the return type of the function. Either int or void. Int is value used for returning something to a call, mainly used for returning integers such as the add function in the following program. Void is used for functions that dont return a value or you dont want to return a value. You must use int or void in every function you make. Take a look at the following program:

#include <stdio.h>

void cfile(char *file)
{
     FILE *fp = fopen(file, "w");
     fprintf(fp, "some text");
     fclose(fp);
}

int add(int x, int y)
{
     int r;
     r = x + y;
     return(r);
}

int main()
{
     cfile("example.txt");
     add(1,1);
     return 0;
}

You could have done this(it really doesn't make a difference):

#include <stdio.h> //standar C header

int cfile(char *file)
{
     FILE *fp = fopen(file, "w");
     fprintf(fp, "example");
     fclose(fp);
     return 0;
}

int add(int x, int y) //this must be int it's returning something to a function call
{
     int r;
     r = x + y;
     return(r);
}

int main()
{
     cfile("example.txt");
     add(1,1);
     return 0;
}