VLSM Calc (C++)

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

using namespace std;

int main(int argc, char **argv){
    if(argc!=2){
        fprintf(stderr, "\n\tNo Arguments or Too Many Arguments.\n\t"
            "Usage: %s [CIDR Integer Value]\n\n", *(argv));
        return 1;
    }
    char *mask, *binary;
    unsigned short cidr, octets=4, binval, i;   //cidr value, number of octets, generic counter

    if(strlen(*(argv+1))<=2){
        /*  I know it's C++ and I didn't use new()  */
        /*      Allocated all in HEAP       */
        mask = (char*)calloc(16, sizeof(char));     // mask in decimal form
        binary = (char*)calloc(9, sizeof(char));    // binary (in string) which will be converted to long later
        if(!mask || !binary){
            /*  I code in C so I prefer stderr  */
            fprintf(stderr, "\n\tCould Not Allocate Heap Space\n");
            return -1;
        }
    }else{
        fprintf(stderr, "\n\tOut Of Range (0-32)\n");   // Again, using stderr. I'm not sure what C++ convention is for errors
        return 1;
    }
    cidr = strtol(*(argv+1), NULL, 10);         // integer value from command line...
    for(octets=0; octets<4; octets++){
        if(cidr>=8){
            cidr -= 8;
            strcat(mask, "255");
        }else{
            if(cidr==0)
                strcat(mask, "0");
            else{
                for(i=0;i<cidr;i++){
                    strcat(binary, "1");
                }
                for(i=0;i<(8-cidr);i++){
                    strcat(binary, "0");
                }
                binval = strtol(binary, NULL, 2);   // Convert to string
                cidr=0;                 // set CIDR to 0 now. It's a subnet mask. No more after the last '1' bit
                free(binary);               // FREE AS A BIRD. AND THIS BIRD YOU CANNOT CHAAAAAANGE
                binary = (char*)calloc(9,sizeof(char)); // I like to zero out things. Especially strings.
                snprintf(binary, 9, "%d", binval);  // Write at MOST 9 bytes.
                strcat(mask, binary);
            }
        }
        if(octets!=3)
            strcat(mask, ".");
    }
    strcat(mask, "\n");
    cout << mask;
    free(binary);
    free(mask);
    return 0;
}