process-args-3

#include <ctype.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int isnum(char *s) {
    for (size_t i = 0; s[i] != 0; ++i) {
        if (s[i] != '+' && s[i] != '-' && !isdigit(s[i])) {
            return 0;
        }
    }
    return 1;
}

int solve(int64_t a) {
    int8_t i8 = (int8_t)a;
    if (i8 == a) {
        return 1;
    }
    int16_t i16 = (int16_t)a;
    if (i16 == a) {
        return 2;
    }
    int32_t i32 = (int32_t)a;
    if (i32 == a) {
        return 4;
    }
    return -1;
}

int main(int argc, char *argv[]) {
    int64_t a;
    char *end;
    for (int i = 1; i < argc; ++i) {
        if (argv[i][0] == 0) {
            puts("-1");
            continue;
        }
        errno = 0;
        a = strtol(argv[i], &end, 10);
        if (errno == 0) {
            if (!isnum(argv[i]) || (*end != 0)) {
                puts("-1");
            } else {
                printf("%d\n", solve(a));
            }
        } else {
            puts("-1");
        }
    }
    return 0;
}