c

// Based on https://stackoverflow.com/a/112956/1438550

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

const char *int_to_binary_str(int x, int N_bits){
    static char b[512];
    char *p = b;
    b[0] = '\0';

    for(int i=(N_bits-1); i>=0; i--){
      *p++ = (x & (1<<i)) ? '1' : '0';
      if(!(i%4)) *p++ = ' ';
    }
    return b;
}

int main() {
  for(int i=31; i>=0; i--){
    printf("0x%08X %s \n", (1<<i), int_to_binary_str((1<<i), 32));
  }
  return 0;
}

期望的行为:

Run:
gcc -pthread -Wformat=0 -lm -o main main.c; ./main

Output:
0x80000000 1000 0000 0000 0000 0000 0000 0000 0000  
0x40000000 0100 0000 0000 0000 0000 0000 0000 0000  
0x20000000 0010 0000 0000 0000 0000 0000 0000 0000  
0x10000000 0001 0000 0000 0000 0000 0000 0000 0000  
0x08000000 0000 1000 0000 0000 0000 0000 0000 0000  
0x04000000 0000 0100 0000 0000 0000 0000 0000 0000  
0x02000000 0000 0010 0000 0000 0000 0000 0000 0000  
0x01000000 0000 0001 0000 0000 0000 0000 0000 0000  
0x00800000 0000 0000 1000 0000 0000 0000 0000 0000  
0x00400000 0000 0000 0100 0000 0000 0000 0000 0000  
0x00200000 0000 0000 0010 0000 0000 0000 0000 0000  
0x00100000 0000 0000 0001 0000 0000 0000 0000 0000  
0x00080000 0000 0000 0000 1000 0000 0000 0000 0000  
0x00040000 0000 0000 0000 0100 0000 0000 0000 0000  
0x00020000 0000 0000 0000 0010 0000 0000 0000 0000  
0x00010000 0000 0000 0000 0001 0000 0000 0000 0000  
0x00008000 0000 0000 0000 0000 1000 0000 0000 0000  
0x00004000 0000 0000 0000 0000 0100 0000 0000 0000  
0x00002000 0000 0000 0000 0000 0010 0000 0000 0000  
0x00001000 0000 0000 0000 0000 0001 0000 0000 0000  
0x00000800 0000 0000 0000 0000 0000 1000 0000 0000  
0x00000400 0000 0000 0000 0000 0000 0100 0000 0000  
0x00000200 0000 0000 0000 0000 0000 0010 0000 0000  
0x00000100 0000 0000 0000 0000 0000 0001 0000 0000  
0x00000080 0000 0000 0000 0000 0000 0000 1000 0000  
0x00000040 0000 0000 0000 0000 0000 0000 0100 0000  
0x00000020 0000 0000 0000 0000 0000 0000 0010 0000  
0x00000010 0000 0000 0000 0000 0000 0000 0001 0000  
0x00000008 0000 0000 0000 0000 0000 0000 0000 1000  
0x00000004 0000 0000 0000 0000 0000 0000 0000 0100  
0x00000002 0000 0000 0000 0000 0000 0000 0000 0010  
0x00000001 0000 0000 0000 0000 0000 0000 0000 0001 

至于我，我为此编写了一些通用代码

#include<stdio.h>
void int2bin(int n, int* bin, int* bin_size, const int  bits);

int main()
{
    char ch;
    ch = 'A';
    int binary[32];
    int binary_size = 0;
    
    int2bin(1324, binary, &binary_size, 32);
    for (int i = 0; i < 32; i++)
    {
        printf("%d  ", binary[i]);
    }
    
    
    return 0;
}

void int2bin(int n, int* bin,int *bin_size,const int  bits)
{
    int i = 0;
    int temp[64];
    for (int j = 0; j < 64; j++)
    {
        temp[j] = 0;
    }
    for (int l = 0; l < bits; l++)
    {
        bin[l] = 0;
    }

    while (n > 0)
    {
        temp[i] = n % 2;
        n = n / 2;
        i++;
    }
    *bin_size = i;

    //reverse modulus values
    for (int k = 0; k < *bin_size; k++)
    {
        bin[bits-*bin_size+k] = temp[*bin_size - 1 - k];
    }
}

但对我来说很管用:

#define BYTE_TO_BINARY_PATTERN "%c%c%c%c%c%c%c%c"
#define BYTE_TO_BINARY(byte)  \
  (byte & 0x80 ? '1' : '0'), \
  (byte & 0x40 ? '1' : '0'), \
  (byte & 0x20 ? '1' : '0'), \
  (byte & 0x10 ? '1' : '0'), \
  (byte & 0x08 ? '1' : '0'), \
  (byte & 0x04 ? '1' : '0'), \
  (byte & 0x02 ? '1' : '0'), \
  (byte & 0x01 ? '1' : '0') 

printf("Leading text "BYTE_TO_BINARY_PATTERN, BYTE_TO_BINARY(byte));

对于多字节类型

printf("m: "BYTE_TO_BINARY_PATTERN" "BYTE_TO_BINARY_PATTERN"\n",
  BYTE_TO_BINARY(m>>8), BYTE_TO_BINARY(m));

不幸的是，你需要所有额外的引号。这种方法存在宏的效率风险(不要将函数作为参数传递给BYTE_TO_BINARY)，但避免了这里的其他一些建议中的内存问题和多次调用strcat。

接下来将向您展示内存布局:

#include <limits>
#include <iostream>
#include <string>

using namespace std;

template<class T> string binary_text(T dec, string byte_separator = " ") {
    char* pch = (char*)&dec;
    string res;
    for (int i = 0; i < sizeof(T); i++) {
        for (int j = 1; j < 8; j++) {
            res.append(pch[i] & 1 ? "1" : "0");
            pch[i] /= 2;
        }
        res.append(byte_separator);
    }
    return res;
}

int main() {
    cout << binary_text(5) << endl;
    cout << binary_text(.1) << endl;

    return 0;
}

下面是一个不受重入性问题或参数大小/类型限制的函数版本:

#define FMT_BUF_SIZE (CHAR_BIT*sizeof(uintmax_t)+1)

char *binary_fmt(uintmax_t x, char buf[static FMT_BUF_SIZE])
{
    char *s = buf + FMT_BUF_SIZE;
    *--s = 0;
    if (!x) *--s = '0';
    for (; x; x /= 2) *--s = '0' + x%2;
    return s;
}

请注意，这段代码适用于2到10之间的任何底数，只要将2替换为所需的底数。用法是:

char tmp[FMT_BUF_SIZE];
printf("%s\n", binary_fmt(x, tmp));

其中x是任意的积分表达式。

这是一个非常简单的例子:

int print_char_to_binary(char ch)
{
    int i;
    for (i=7; i>=0; i--)
        printf("%hd ", ((ch & (1<<i))>>i));
    printf("\n");
    return 0;
}