[C++知识库]【C语言随笔1】整型转32位比特串（数组方式存储比特数）

// Code file created by C Code Develop
#include "stdio.h"
#include "stdlib.h"

void int2binary(int num){
    int bi[32]; // 存储比特值
    int k[31] = 
    {
    0x40000000,0x20000000,0x10000000, 
    0x8000000,0x4000000,0x2000000, 
    0x1000000,0x800000,0x400000,
    0x200000,0x100000,0x80000,
    0x40000,0x20000,0x10000,
    0x8000,0x4000,0x2000,
    0x1000,0x800,0x400,
    0x200,0x100,0x80,
    0x40,0x20,0x10,
    0x8,0x4,0x2,0x1
    }; // 除基取余法
    int r, cf = 1; //r用于计算 cf进位标志位
    
    // 判断正负
    if(num >= 0) {
        bi[0] = 0; 
        r = num;
    }
    else {
        bi[0] = 1;  // 负数最高位为1
        r = -1*num; // 先取原码
    }
    
    // 取原码
    for (int i = 1; i < 32; ++i) {
        bi[i] = r/k[i - 1];
        r -= k[i - 1]*bi[i];
    }
    
    // 负数原码转补码
    if (bi[0]) {
        // 按位取反
        for (int i = 1; i < 32; ++i) {
            if (bi[i] == 0) bi[i] = 1;
            else bi[i] = 0;
        }
        
        // 反码加一
        for (int i = 31; i > 0; --i) {
            if (cf) {
                if (bi[i]) bi[i] = 0;
                else {
                    bi[i] = 1;
                    cf = 0;
                }
            }
        }
    }
    
    // 打印输出比特串
    for (int i = 0; i < 32; i++) {
        printf("%d", bi[i]);
    }
    printf("\n");
}


int main(int argc, char **argv) 
{
    int2binary(-500); // 0xfffffe0c
    return 0;
}