dec2bin.c

//dec2bin - A program to convert a decimal number to binary
//Made by atm959 on January 27th, 2023

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

typedef unsigned char bool;
#define false 0
#define true 1

void dec2bin(char* res, unsigned long long num, bool withSeparaters, bool withNumbers){
    unsigned long long mask = 0x8000000000000000;

    for(int i = 0; i < 64; i++){
        if(withSeparaters){
            if((i % 8) == 0){
                strcat(res, "|");
            }
        }

        unsigned long long bit = num & mask;
        strcat(res, bit ? "1" : "0");
        mask = mask >> 1;
    }

    if(withNumbers){
        strcat(res, "\n");

        unsigned char bitNum = 64;
        for(int i = 0; i < 64; i++){
            if(((i % 8) == 0)){
                if(withSeparaters){
                    strcat(res, "|");
                }

                char numStr[3];
                sprintf(numStr, "%d", bitNum);
                strcat(res, numStr);

                int numSpaces = 8 - strlen(numStr);
                for(int i = 0; i < numSpaces; i++){
                    strcat(res, " ");
                }

                bitNum -= 8;
            }
        }
    }
}

int main(int argc, char** argv){
    if(argc < 2){
        printf("Usage: dec2bin [num] [options]\n");
        printf("\tnum - The number to convert to binary\n");
        printf("\toptions - can be one or both of these, with a space between them:\n");
        printf("\t\t-n - Show bit numbers under the bits\n");
        printf("\t\t-s - Have separaters between every 8 bits\n");
    } else {
        bool withNumbers = false;
        bool withSeparaters = false;
        if(argc > 2){
            for(int i = 2; i < argc; i++){
                if(strcmp(argv[i], "-n") == 0) withNumbers = true;
                if(strcmp(argv[i], "-s") == 0) withSeparaters = true;
            }
        }

        unsigned long long num = atoi(argv[1]);

        char binStr[73*2];
        strcpy(binStr, "");
        dec2bin(binStr, num, withSeparaters, withNumbers);
        printf("%s\n", binStr);
    }
}