字符串下标超出范围。字符串大小未知并循环字符串直到 null

发布于 2024-10-15 02:57:26 字数 391 浏览 2 评论 0原文

#include<iostream>
#include<cmath>
#include<iomanip>
#include<string>

using namespace std;

int main()
{
 string word;
 int j = 0;

 cin >> word;

 while(word[j]){
 cout << "idk";
 j++;
 }
 cout << "nope";



 system("pause");
 return 0;
}

这只是一个测试这个循环的小试验程序。我正在开发的程序是关于元音并根据用户确定的序列打印元音的。在用户输入之前，该字符串不会被定义。提前感谢你们的帮助。

原文

#include<iostream>
#include<cmath>
#include<iomanip>
#include<string>

using namespace std;

int main()
{
 string word;
 int j = 0;

 cin >> word;

 while(word[j]){
 cout << "idk";
 j++;
 }
 cout << "nope";



 system("pause");
 return 0;
}

This is just a little trial program to test this loop out. The program I am working on is about vowels and printing vowels out from a sequence determined by the user. The string isn't defined until the user types in. Thank you for your guys help in advance.

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秋心╮凉 2024-10-22 02:57:26

在你的循环中尝试这个：

while(j < word.size()){
  cout << "idk";
  j++;
}

Try this for your loop:

while(j < word.size()){
  cout << "idk";
  j++;
}

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手心的温暖 2024-10-22 02:57:26

std::string 的大小并非未知 - 您可以使用 std::string::size() 成员函数获取它。另请注意，与 C 字符串不同，std::string 类不必以 null 终止，因此您不能依赖 null 字符来终止循环。

事实上，使用 std::string 更好，因为您始终知道大小。与所有 C++ 容器一样，std::string 也带有内置迭代器，它允许您安全地循环字符串中的每个字符。 std::string::begin() 成员函数为您提供一个指向字符串开头的迭代器，而 std::string::end() 函数为您提供一个指向最后一个字符之后的迭代器。

我建议熟悉 C++ 迭代器。使用迭代器处理字符串的典型循环可能如下所示：

for (std::string::iterator it = word.begin(); it != word.end(); ++it)
{
   // Do something with the current character by dereferencing the iterator
   // 
   *it = std::toupper(*it); // change each character to uppercase, for example
}

The size of an std::string is not unknown - you can get it using the std::string::size() member function. Also note that unlike C-strings, the std::string class does not have to be null-terminated, so you can't rely on a null-character to terminate a loop.

In fact, it's much nicer to work with std::string because you always know the size. Like all C++ containers, std::string also comes with built-in iterators, which allow you to safely loop over each character in the string. The std::string::begin() member function gives you an iterator pointing to the beginning of the string, and the std::string::end() function gives you an iterator pointing to one past the last character.

I'd recommend becoming comfortable with C++ iterators. A typical loop using iterators to process the string might look like:

for (std::string::iterator it = word.begin(); it != word.end(); ++it)
{
   // Do something with the current character by dereferencing the iterator
   // 
   *it = std::toupper(*it); // change each character to uppercase, for example
}

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~没有更多了~