/*
 * Program to echo command-line arguments, one per line, and do a little
 * processing of each (to illustrate working with strings).
 */
#include <stdio.h>
#include <stdlib.h>

/* returns length of string (i.e., same functionality as strlen() */
int mylength(char* s) {
    int count = 0;
    while (*s != '\0') {
        ++s; ++count;
    }
    return count;
}

/* main program */
int main(int argc, char* argv[]) {

    long n;
    char* endptr;

    for (int i = 0; i < argc; ++i) {
        printf("argv[%d] is '%s'\n", i, argv[i]);

        /* try to convert string to long int */
        n = strtol(argv[i], &endptr, 10);
        if (*endptr == '\0') {
            printf("an integer (%ld)\n", n);
        }
        else {
            printf("not an integer (%d characters not read)\n",
                    mylength(endptr));
        }
    }
    return EXIT_SUCCESS;
}