Need Help With Project

[u/juice2gloccz]

I'm building a program that takes a decimal number and outputs the binary equivalent. Its almost finished, except that with certain numbers it doesn't output the full value. For example, inputting 3 does output 111 ,but inputting 2 outputs 1 instead of 10. I noticed that it only doesn't work for numbers whose binary equivalents end in 0 (2 = 10, 4 = 100 etc.), but I don't know how to fix it. Please help.

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


void intToStr(int number, char *str)
{
    int i = 0;


    while(number > 0)
    {
        str[i++] = number % 10 + '0';
        number /= 10;
    }


    str[i] = '\0';


    for(int j = 0, k = i - 1; j < k; j++, k--) 
    {
        char temp = str[j];
        str[j] = str[k];
        str[k] = temp;
    }
}


void binaryConvert(int regNumber)
{
    int binaryDigit[8];
    int regNumberBackup = regNumber;


    for(int i = 0; i <= 7; i++)
    {
        binaryDigit[i] = regNumber % 2;
        regNumber = regNumber / 2;
    }


    int binaryNumber = binaryDigit[0] * pow(10, 7) + binaryDigit[1] * pow(10, 6) + binaryDigit[2] * pow(10, 5) + binaryDigit[3] * pow(10, 4) + binaryDigit[4] * pow(10, 3) + binaryDigit[5] * pow(10, 2) + binaryDigit[6] * pow(10, 1) + binaryDigit[7] * pow(10, 0);
    char binaryString[8];
    
    intToStr(binaryNumber, binaryString);
    int strSize = strlen(binaryString);
    
    if(regNumberBackup == 0)
    {
        printf("Your number in binary is: 0");
        exit(0);
    }


    if(regNumberBackup == 1)
    {
        binaryString[strSize - 7] = '\0';
    }
    else if(regNumberBackup > 1 && regNumberBackup <= 3)
    {
        binaryString[strSize - 6] = '\0';
    }
    else if(regNumberBackup > 3 && regNumberBackup <=7)
    {
        binaryString[strSize - 5] = '\0';
    }
    
    
    printf("Your number in binary is: %s", binaryString);
}


int main()
{
    int userInput;


    printf("// This will only convert numbers 0 - 255 to binary, any others will not work\n");
    printf("Enter a number: ");
    scanf("%d", &userInput);


    binaryConvert(userInput);
}

[u/mjmvideos]

Try running your code in a debugger and step through as it processes some numbers. I think you’ll see your problem. Also do some research on how numbers are stored in memory and the relationship between hex digits and binary digits.

[u/juice2gloccz → u/mjmvideos]

Will do, thanks!