Question

所以我想：

在do while循环中进行双输入验证
检查是否已完成移动以及是否为逻辑输入。（＃1-9）

我原本以为if else语句但我不确定如何使用else语句返回循环的开头。

do
{
  cout << "Interesting move, What is your next choice?: ";
  cin >> play;
  Pused[1] = play;
  if(play != Pused[0] && play != cantuse[0] && play != cantuse[1] )
  {
    switch(play)
    {
      default:cout << "Your choice is incorrect\n\n";
      break;
    }   
  }
  else
  { }
}    
while(play != 1 && play != 2 && play != 3 && play != 4 && play != 5 && play != 6 && play != 7 && play != 8 && play != 9);
Dis_board(board);

Answer 1

使用“continue”关键字返回循环开始。

Answer 2

只需删除else即可。我认为这不是必需的。如果满足while中的条件，则会自动继续循环。

Answer 3

你的问题有点难以理解，但你在这个循环中有一些条件需要解决：

询问用户输入
检查用户输入是否有效（1-9之间，之前未使用过）
如果我们有一个有效的选择，则退出循环

所以我们需要记录已完成的动作，并检查用户的输入是否在有效选择范围内，我们可以使用仅在选择有效选项时退出的循环。

int choice;
bool used[9] = { false }; // Set all values to false
std::cout << "Interesting move, what is your next choice?: ";
do {
    std::cin >> choice;
    // Here we check if the choice is within the range we care about
    // and not used, note if the first condition isn't true then
    // the second condition won't be evaluated, so if choice is 11
    // we won't check used[10] because the && will short circuit, this
    // lets us avoid array out of bounds. We also need to
    // offset the choice by 1 for the array because arrays in C++
    // are indexed from 0 so used runs from used[0] to used[8]
    if((choice >= 1 && choice <= 9) && !used[choice - 1]) {
        // If we're here we have a valid choice, mark it as used
        // and leave the loop
        used[choice - 1] = true;
        break; // Exit the loop regardless of the while condition
    }

    // If we've made it here it means the above if failed and we have
    // an invalid choice. Restart the loop!
    std::cout << "\nInvalid choice! Input: ";
} while (true);

双输入验证C ++程序的麻烦

3 个答案: