Question

我正在无限期地在一个函数（double）上用C ++循环创建一个软件。在第一次循环之后，第二次运行循环，它返回'nan'。我哪里出错了。

int main()
{
   double Balance = 100;

   for (int i = 0; i < 5; i++) {
      nyaradzo(Balance, i);
   }
}

double nyaradzo(double bal, int pass)
{
   int x = bal;
   double Amount;
   string policy_number;
   double confirmation;

   cout<<"WELCOME TO NYARADZO ONLINE POLICY PAYMENT"<<endl;
   cout<<"ENTER YOUR POLICY NUMBER"<<endl;
   cin>>policy_number;
   cout<<"ENTER AMOUNT YOU WISH TO PAY FOR YOU POLICY"<<endl;
   cin>>Amount;
   cout<<"YOUR POLICY NUMBER IS: "<<policy_number<<endl;
   cout<<"YOU HAVE CHOSEN TO PAY $"<<Amount<<" FOR YOUR FUNERAL POLICY. \n Is this information correct?"<<endl;
   cout<<"1 TO CONFIRM"<<endl;
   cout<<"2 TO CANCEL"<<endl;
   cin>>confirmation;
   if (confirmation==1) {
      if (Amount <= x) {
         x -= Amount;
         cout<<"Transaction Complete"<<endl;
         cout<<"YOUR BALANCE IS $"<<x<<endl;
         return x;
      }
      else if (Amount > x) {
         cout<<"TRANSACTION DENIED \a"<<endl;
         cout<<"You cannot withdraw more than your actual balance..."<<endl;
         return 0;
      }
      else {
         cout <<x  << endl;
         cout<<"TRANSACTION DENIED \a"<<endl;
         cout<<"Your purchase must be greater than or at least equal to $1"<<endl;
        return 0;
      }
   }
   else if (confirmation==2) {
      cout<<"YOU HAVE CHOSEN TO CANCEL YOUR ZESA TRANSACTION"<<endl;
      //    transaction(bal, pass);
   }

   else 

{

cout << "Invalid selection" << endl;
return 0;

}
    }

当它第二次进入循环时，它会失败。

Answer 1

并非nyaradzo中的所有路径都返回值。您应该启用所有编译器警告。它应该提醒你这一点。由于x = bal并且您只在amout确定时修改x，因此将其添加为func的最后一行：

return x;

将x的类型更改为double。或者摆脱x并始终使用bal。

另外，我假设您想保持运行平衡。然后你应该将for循环更改为：

for (int i = 0; i < 5; i++) {
  Balance = nyaradzo(Balance, i);
}

函数在C ++中返回NaN

1 个答案: