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

int main(void)
{
        char buf5[5];
        char buf20[20];
        char *s1 = "01234567890";
        char *s2 = "abcdefghijklmnopqrstuvwxyz";
        int len;

        len = snprintf(buf5, sizeof(buf5), "%s", s1);
        printf("copy to buf5:  s1=\"%s\", len-s1=%d, str-in-buf=\"%s\", len-str-in-buf=%ld\n",
               s1, len, buf5, strlen(buf5));

        len = snprintf(buf20, sizeof(buf20), "%s", s1);
        printf("copy to buf20: s1=\"%s\", len-s1=%d, str-in-buf=\"%s\", len-str-in-buf=%ld\n",
               s1, len, buf20, strlen(buf20));

        len = snprintf(buf20, sizeof(buf20), "%s%s", s1, s2);
        printf("cat  to buf20: s2=\"%s\", len-s1s2=%d, str-in-buf=\"%s\", len-str-in-buf=%ld\n",
               s2, len, buf20, strlen(buf20));

        return 0;
}