C/C++语言整数转二进制字符串代码

不用非标准库函数，自己随手写一个转换函数：

#include <stdio.h>

void convert(unsigned char c, unsigned char* out){
    for(int i=0; i<8; i++) {
        *(out+i) = (c & (0x80 >> i))==0 ? 0x30 : 0x31;
    }
}

int main() {
    unsigned char buf[9] = {0};
    long long int a = 0x0123456789abcdef;
    unsigned char* p = (unsigned char*)&a;

    for(int i=0; i<sizeof(a); i++){
        convert(*(p+i), buf);
        printf("%s
", buf);
    }

    return 0;
}