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 don't return a value or you don't want to return a value. You must use int or void in every function you make. Take a look at the following program:

<source lang="c">

1. 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;

} </source>

You could have done this(it really doesn't make a difference): <source lang="c">

1. include <stdio.h> //standard 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;

} </source>