C++致命错误LNK1120：1个未解决的外部引用

这个错误是什么原因造成的？我谷歌了一下，发现前几个解决方案都说库或主函数有问题，但在我的情况下它们似乎都没问题，我甚至重新打了一遍！可能是什么原因导致的呢？

这可能有所帮助：

MSVCRTD.lib(crtexew.obj) : error LNK2019: unresolved external symbol WinMain@16 referenced in function __tmainCRTStartup

#include <iostream>
using namespace std;
int main()
{
    const double A = 15.0, 
                 B = 12.0, 
                 C = 9.0;
    double aTotal, bTotal, cTotal, total;
    int numSold;

    cout << "Enter The Number of Class A Tickets Sold: ";
    cin >> numSold;
    aTotal = numSold * A;

    cout << "Enter The Number of Class B Tickets Sold: ";
    cin >> numSold;
    bTotal = numSold * B;

    cout << "Enter The Number of Class C Tickets Sold: ";
    cin >> numSold;
    cTotal = numSold * C;

    total = aTotal + bTotal + cTotal;

    cout << "Income Generated" << endl;
    cout << "From Class A Seats $" << aTotal << endl;
    cout << "From Class B Seats $" << bTotal << endl;
    cout << "From Class C Seats $" << cTotal << endl;
    cout << "-----------------------" << endl;
    cout << "Total Income: " << total << endl;

    return 0;
}