hello.c

#include <stdio.h>
#include <locale.h>
#include <string.h>

void center_string(char *res_buf, char *s, int len)
{

    int l_offset, r_offset;

    l_offset = r_offset = (len - len % 2) / 2;

    int slen = strlen(s);

    int str_right_half = (slen - slen % 2) / 2;
    l_offset += str_right_half;
    r_offset -= str_right_half;

    char format_str[9];

    sprintf(format_str, "%%%ds%%%ds", l_offset, r_offset);
    sprintf(res_buf, format_str, s, " ");
}

void subst(char *s, char from, char to)
{
    while (*s == from)
        *s++ = to;
}


int main(void)
{

    char *locale = setlocale(LC_ALL, "");

    char buf[81];

    sprintf(buf, "%080d", 0);
    subst(buf, '0', '*');

    printf("%s\n", buf);

    char res_buf[81];
    center_string(res_buf, "Leben ist schaisse!", 78);
    printf("*\x1b[32m%s\x1b[0m*\n", res_buf);

    printf("%s\n", buf);

    center_string(res_buf, "Wir alle sterben!", 78);
    printf("*\x1b[35m%s\x1b[0m*\n", res_buf);

    printf("%s\n", buf);
    return 0;
}