错误：预期的';'在'generationString'之前[关闭]答案

【问题标题】：error: expected ‘;’ before ‘generationString’ [closed]错误：预期的';'在'generationString'之前[关闭]
【发布时间】：2018-10-24 12:56:28
【问题描述】：

我目前正在尝试解决我在使用此代码时遇到的一些问题，但无法真正弄清楚为什么会出现这 2 个错误。我试图查看是否有东西没有关闭，但这似乎不是这种情况，可能是“：”之间的距离造成的？我现在只是在抓稻草..

main.cpp:30:38: error: expected ‘;’ before ‘generationString’
cout << "Generation " << x << ": " generationString << endl;

main.cpp:54:40: error: expected ‘;’ before ‘generationString’
cout << "Generation " << x++ << ": " generationString << endl;

尝试编译此代码时：

#include <iostream>

using namespace std;

string
initString ()
{
}

int
calculateScore (string guess, string target)
{
}

string
mutate (string mutationString)
{
}


int
main ()
{
  string targetString = "METHINKS IT IS LIKE A WEASEL";
  string generationString = initString ();
  string currentString = generationString;

  int score = calculateScore (currentString, targetString);
  int x = 0;
  cout << "Generation " << x << ": " generationString << endl;
  do
    {
      for (int i = 0; i < 100; i++)
    {
      string newCopy = generationString;
      newCopy = mutate (newCopy);
      int copyScore = calculateScore (newCopy, targetString);

      if (copyScore > score)
        {
      currentString = newCopy;
      score = copyScore;
      if (copyScore == targetString.length ())
    {
      break;
    }

    }
}
  generationString = currentString;

     }
  while (score < targetString.length ());
  cout << "Generation " << x++ << ": " generationString << endl;
  return 0;
  }

【问题讨论】：

": " generationString -> ": " << generationString。投票结束是错字。
是的，肯定是错字问题。如果您单独发布此内容，我可以添加为答案。
错字问题应该被标记为这样。不予回答。

标签： c++ output ostream

【解决方案1】：

您缺少<<。

cout << "Generation " << x << ": " generationString << endl;

应该是

cout << "Generation " << x << ": " << generationString << endl;

同样

cout << "Generation " << x++ << ": " generationString << endl;

应该是这样的

cout << "Generation " << x++ << ": " << generationString << endl;

【讨论】：

【解决方案2】：

您可能在该行中缺少<<

cout << "Generation " << x << ": " generationString << endl;

给你

": " generationString

应该是

": " << generationString

C++ 可以连接文字字符串，但它不能连接文字字符串和其他任何东西（比如 std::strings）。所以例如这会起作用

cout << "Generation " << x << ": " "METHINKS IT IS LIKE A WEASEL" << endl;

【讨论】：