Public Wrapper

A wrapper function can present a small interface over lower-level details.

public_wrapper.c

#include <stdio.h>

static int rectangle_area(int width, int height) {
    return width * height;
}

int main(void) {
    int width = ;
    int height = 5;
    int area = rectangle_area(width, height);

    printf("area=%d\n", area);
    return 0;
}

#include <stdio.h>

static int rectangle_area(int width, int height) {
    return width * height;
}

int main(void) {
    int width = ;
    int height = 5;
    int area = rectangle_area(width, height);

    printf("area=%d\n", area);
    return 0;
}

#include <stdio.h>

static int rectangle_area(int width, int height) {
    return width * height;
}

int main(void) {
    int width = ;
    int height = 5;
    int area = rectangle_area(width, height);

    printf("area=%d\n", area);
    return 0;
}

interface function The caller uses a simple function name instead of repeating the formula.

implementation detail The formula can change inside the wrapper without changing the call site.