Using #define

/* 2301.c: Using #define */
#include <stdio.h>

#define METHOD "ABS"
#define ABS(val) ((val) < 0 ? -(val) : (val))
#define MAX_LEN 8
#define NEGATIVE_NUM -10

main(void)
{
    char *str = METHOD;
    int array[MAX_LEN];
    int i;

    printf("The orignal values in array:\n");
    for (i=0; i<MAX_LEN; i++){
    array[i] = (i + 1) * NEGATIVE_NUM;
    printf("array[%d]: %d\n", i, array[i]);
    }

    printf("\nApplying the %s macro:\n", str);
    for (i=0; i<MAX_LEN; i++){
    printf("ABS(%d): %3d\n", array[i], ABS(array[i]));
    }

    return 0;
}