Question

A program called i2b.c was implemented with the intention to provide a binary representation of an integer. Unfortunately, the implementation has the following limitation:

• It was hard-coded to only convert a single number.
• The conversion algorithm only works for positive number.

Modify the existing source code of i2b.c such that:

• i2b.c can now accept a single command line argument. This command line argument is assumed to be a valid signed integer.
• i2b.c will convert the command line argument into its corresponding binary representation with the following condition:
  • The representation is an array of integers.
  • This array has a length of 32.
  • This array contains the binary representations of the integer argument.
  • Index 0 contains the most significant bit, and index 31 contains the least significant bit.
• i2b.c will print out the final binary representation on a single line without any space between the bits.

PROGRAM BELOW

#include <stdio.h>

#define N 32

int main(int argc, char *argv[]) {

  int n = 12345;

  int binRep[N];

  int i;

  for (i = 0; i < N; i++) {

    binRep[i] = 0;

  }

  i = 0;

  while (n > 0) {

    binRep[i] = n % 2;

    n = n / 2;

    i++;

  }

  for (i = N - 1; i >= 0; i--) {

    printf("%d", binRep[i]);

  }

  printf("\n");

  return 0;

}

Answer 1

// according to your code

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

int main(int argc, char *argv[]) 
{ 
    if (argc != 2){
        puts("usage: i2b <number>");
        return -1;
    }

    int32_t n = atoi(argv[1]);

    int binaryNum[32] = {}; 
    int i = 0; 
    
    while (n > 0 && i < 32) { 
        binaryNum[i] = n % 2; 
        n = n / 2; 
        i++;
    } 
    
    if(n >= 0){
        binaryNum[31]=0;
    } else {
        binaryNum[31]=1;
    }

    for (int i = 31; i > -1; i--){
        printf("%d", binaryNum[i]);
    }
    
    puts("");
    return 0; 
}
/*better implementation
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

int main(int argc, char *argv[]){ 

    if (argc != 2){
        puts("usage: i2b <number>");
        return -1;
    }

    int32_t number = atoi(argv[1]);

    for(int i = 31; i > -1; i--){
        printf("%d", (number >> i) & 1);
    }
    puts("");
    return 0;
}

*/