十进制数转换为二进制数的两种方法

下面代码仅供本人复习所用，实用性N低，各位飘过吧~~哈哈:>

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//

// 十进制转二进制.

//

 

#include <cstdlib>

#include <iostream>

#include <vector>

 

//

// 使用 unsigned long long 类型数值来表示二进制数，

// 由于这样表示的二进制数位数有限，顾输入参数为 unsigned short 类型.

//

unsigned long long toBinary(unsigned short decimal)

{

    long long binary = 0;

    long long carry = 1;

    while (0 < decimal) {

        binary += decimal % 2 ? carry : 0;

        carry *= 10;

        decimal /= 2;

    }

    return binary;

}

 

//

// 使用向量保存二进制数字符串.

//

void toBinary_vector(unsigned long decimal, std::vector<char> &binary)

{

    while (0 < decimal) {

        binary.push_back(decimal % 2 + '0');

        decimal /= 2;

    }

}

 

//

// 测试.

//

int main(void)

{

    std::cout << "Input decimal number: ";

     

    unsigned short decimal;

    while (!(std::cin >> decimal)) {

        std::cin.sync();

        std::cin.clear();

        std::cout << "Input wrong, please input again: ";

    }

    std::cout << "Binary: " << toBinary(decimal) << std::endl;

     

    std::vector<char> binary;

     

    toBinary_vector(decimal, binary);

    std::vector<char>::iterator beg = binary.begin();

    std::vector<char>::iterator end = binary.end();

    std::cout << "Binary: ";

    while (beg != end--) {

        std::cout << *end;

    }

    std::cout << std::endl;

  

    return EXIT_SUCCESS;

}