c++ - 我没有任何编译错误，但我的代码无法工作。怎么了？

Question

我正在做一个简单的程序，我接受电话号码的前四位数字，并且必须生成其余数字的所有可能性。最后 6 位数字之和必须等于 33。如果第四位数字为奇数，则第五位数字必须为偶数，如果第四位数字为偶数，则第五位数字必须为奇数。

我已经确定它没有将数字相加，并且函数plotNumbers() 中的for 循环实际上没有循环。我完全迷失了。大家有什么想法吗？

#include "stdafx.h"
#include <iostream>
#include <vector>

using namespace std;

void plotNumbers(vector<int> number1, int digit1, int digit2, int digit3, int digit4);
bool findTrueFalse(vector<int> vec);

int _tmain(int argc, _TCHAR* argv[])
{
int digit1, digit2, digit3, digit4;
vector<int> number;

cout << "Enter the first four digits:\n";
cin >> digit1;
cin >> digit2;
cin >> digit3;
cin >> digit4;

if (digit4 == 0 || digit4 == 2 || digit4 == 4 || digit4 == 6 || digit4 == 8)
{
    number.push_back(1);        
    plotNumbers(number, digit1, digit2, digit3, digit4);
}
else if (digit4 == 1 || digit4 == 3 || digit4 == 5 || digit4 == 7 || digit4 == 9)
{
    number.push_back(0);
    plotNumbers(number, digit1, digit2, digit3, digit4);
}
else
{
    cout << "\nYou entered an illegal value.  Good-bye.\n\n";
}

system("pause");
return 0;
}

void plotNumbers(vector<int> number1, int digit1, int digit2, int digit3, int digit4)
{

for ( ; number1[0] < 10; number1[0] += 2)
{
    number1.push_back(0);


    for ( ; number1[1] < 10; ++number1[1])
    {
        number1.push_back(0);


        for ( ; number1[2] < 10; ++number1[2])
        {
            number1.push_back(0);


            for ( ; number1[3] < 10; ++number1[3])
            {
                number1.push_back(0);


                for ( ; number1[4] < 10; ++number1[4])
                {
                    number1.push_back(0);


                    for ( ; number1[5] < 10; ++number1[5])
                    {

                        bool total33 = findTrueFalse(number1);

                        if (total33)
                        {
                            cout << "(" << digit1 << digit2 << digit3 << ") ";
                            cout << digit4 << number1[0] << number1[1] << " - ";
                            cout << number1[2] << number1[3] << number1[4] << number1[5] << endl;
                        }
                    }
                }
            }
        }
    }
}
}

bool findTrueFalse(vector<int> vec)
{
int total = 0;
vector<int>::iterator postIt;

for (postIt = vec.begin(); postIt != vec.end(); ++postIt)
{
    total += *postIt;
}

if (total == 33)
{
    return true;
}
else
{
    return false;
}

}

Answer 1

首先，尝试使用短代码以避免出现以下错误:

if (digit4 % 2 == 0)

而不是

if (digit4 == 0 || digit4 == 2 || digit4 == 4 || digit4 == 6 || digit4 == 8)

其次，您只需执行一次 number1.pushback(0) ，但您要执行多次。您知道运行 number1.pushback(0) 时会发生什么吗？我想不是:

• 它会在 vector number1 末尾添加一个值为 0 的新元素

我建议使用以下代码(您进行缩进):

#include "stdafx.h"
#include <iostream>
#include <vector>

using namespace std;

void plotNumbers(vector<int> number1, int digit1, int digit2, int digit3, int digit4);
bool findTrueFalse(vector<int> vec);

int _tmain(int argc, _TCHAR* argv[])
{
int digit1, digit2, digit3, digit4;
vector<int> number;

cout << "Enter the first four digits:\n";
cin >> digit1;
cin >> digit2;
cin >> digit3;
cin >> digit4;

if (digit4 % 2 == 0)
{
    number.push_back(1);        
    for (int i=0; i<5; i++)
        number.push_back(0);
    plotNumbers(number, digit1, digit2, digit3, digit4);
}
else if (digit4 % 2 == 1)
{
    number.push_back(0);
    for (int i=0; i<5; i++)
        number.push_back(0);
    plotNumbers(number, digit1, digit2, digit3, digit4);
}
else
{
    cout << "\nYou entered an illegal value.  Good-bye.\n\n";
}

system("pause");
return 0;
}

void plotNumbers(vector<int> number1, int digit1, int digit2, int digit3, int digit4)
{

for ( ; number1[0] < 10; number1[0] += 2)
{
    number1[1] = 0;


    for ( ; number1[1] < 10; ++number1[1])
    {
        number1[2] = 0;


        for ( ; number1[2] < 10; ++number1[2])
        {
            number1[3] = 0;


            for ( ; number1[3] < 10; ++number1[3])
            {
                number1[4] = 0;


                for ( ; number1[4] < 10; ++number1[4])
                {
                    number1[5] = 0;


                    for ( ; number1[5] < 10; ++number1[5])
                    {

                        bool total33 = findTrueFalse(number1);

                        if (total33)
                        {
                            cout << "(" << digit1 << digit2 << digit3 << ") ";
                            cout << digit4 << number1[0] << number1[1] << " - ";
                            cout << number1[2] << number1[3] << number1[4] << number1[5] << endl;
                        }
                    }
                }
            }
        }
    }
}
}

bool findTrueFalse(vector<int> vec)
{
int total = 0;
vector<int>::iterator postIt;

for (postIt = vec.begin(); postIt != vec.end(); ++postIt)
{
    total += *postIt;
}

if (total == 33)
{
    return true;
}
else
{
    return false;
}

}