sovavucks.c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int array[] = {
1000000000,
2000000000,
3000000000,
4000000000,
5000000000
};

void revarray(void *base, unsigned long nel, unsigned long width){
    char *carr = (char*) base, tmp;
    unsigned long i, j;
    for (i = 0; i < nel / 2; i++){
        for (j = 0; j < width; j++){
            tmp = *(carr + i * width + j);
            *(carr + i * width + j) = *(carr + (nel - i - 1) * width + j);
            *(carr + width * (nel - i - 1) + j) = tmp;
        }
    }
}

int main(int argc, char **argv){
    revarray(array, 5, sizeof(int));
    int i;
    for (i = 0; i < 5; i++) {
        printf("%d\n", array[i]);
    }

    return 0;
}