Cでランダムな文字列を得る

前にも Ruby や Python でやったネタだけども。

#include
#include
#include
#include

int main(int argc, char *argv[])
{
    int i;
    char strpool[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    int lenpool = strlen(strpool);
    int l, r;

    l = atoi(argv[1]);
    char strrand[l + 1];

    srand((unsigned) time(NULL));

    for (i = 0; i < l; i++) {
        r = rand() % lenpool;
        strrand[i] = strpool[r];
     }
    strrand[l] = '\0';
    printf("%s\n", strrand); return 0;
}

takatoh@nightschool $ gcc -Wall -o strrand strrand.c
takatoh@nightschool $ ./strrand 20
hiVKZhO2rwtlDPUJmdo7