c++ - C++十进制转十六进制代码

Question

我是 C++ 编程的新手。我的任务是编写十进制到十六进制的转换代码。这是我到目前为止所做的。

#include <iostream>

int main()
{
    long dec;
    int rem;

    std::cout << "enter decimal number: ";
    std::cin >> dec;

    while (dec > 0) {
        rem = dec % 16;
        if (rem > 9) {
            switch (rem) {
               case 10: std::cout << "A"; break;
               case 11: std::cout << "B"; break;
               case 12: std::cout << "C"; break;
               case 13: std::cout << "D"; break;
               case 14: std::cout << "E"; break;
               case 15: std::cout << "F"; break;
            }
        }
        else {
            std::cout << rem;
        }
        dec = dec / 16;
    }
}

它向后给出答案，比如如果我输入一个十进制数“650”，它给出十六进制值 A82，而答案应该是 28A。谁能建议我应该如何纠正它？

Answer 1

最简单的解决方案:

#include <iostream>
using namespace std;
int main(){
    int val;
    cin >> val;
    cout << hex << val << endl;
    return 0;
}

算法的修复 - 使用递归:

#include <iostream>
#include <conio.h>
using namespace std;

void print_hex(int value)
{
    if (value == 0)
        return;

    int rem = value % 16;
    value /= 16;
    print_hex(value); //first execute recurency and print next value

    //after return print the less significant digit
    if (rem > 9)
        cout << (char)(rem - 10 + 'A');
    else
        cout << rem;
}

int main(int argc, char * argv[]) {
    cout << "enter decimal number: ";
    long dec;
    cin >> dec;
    print_hex(dec);
    cout << endl;
    return 0;
}