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

int my_atoi(char* s) {
    int n = 0;
    int sign = 1;
    if(s[0] == '-') {
        sign = -1;
        s = &s[1];
    }
    while(s[0] != '\0') {
        n *= 10;
        n += s[0] - '0';
        s = &s[1];
    }
    n *= sign;
    return n;
}
int main(int argc, char* argv[]) {
    char* test_strings[] = {"123", "1", "15", "-15", "-23"};
    // WRONG
    // int num_test_strings = sizeof(test_strings);

    // RIGHT
    int num_test_strings = sizeof(test_strings) / sizeof(test_strings[0]);

    printf("There are %d test strings.\n", num_test_strings);
    for(int i = 0; i < num_test_strings; i++) {
        int n = my_atoi(test_strings[i]);
        printf("%s ==> %d\n", test_strings[i], n);
    }
    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */