“字符串下标超出范围"；从字符数组更改为字符串时出错? [英] "String subscript out of range" error when changing from character array to string?

问题描述

我开始使用字符串代替字符数组，并且在将定义为5的字符数组之一更改为字符串时遇到错误.尝试运行程序时出现的错误是表达式:字符串下标超出范围".

I'm starting to use strings in place of character arrays and am encountering an error when I change one of my character arrays defined with a size of 5 to a string. The error I get is "Expression: string subscript out of range" upon trying to run the program.

"newWord"最初是一个字符数组，但是将其更改为字符串后，出现此错误.我不明白是什么原因导致的，使用字符数组时程序运行良好.

"newWord" was originally a character array, but upon changing it to a string I'm getting this error. I don't understand what could be causing this, when using the character array the program performs fine.

int main() {
fstream inputFile;
fstream outputFile;
string newWord;
int i, k;
string word;
inputFile.open( "H:\\word.txt" );
outputFile.open( "H:\\newword.txt" );
if( inputFile )
{
    while( getline( inputFile, word ) )
    {
        for( i = 0; i < (word.length()- 3); ++i )
        {
            for( k = 0; k < 4; ++k )
                newWord[k] = word[i+k];
            cout << newWord << endl;
            outputFile << newWord << endl;
        }
    }
}
return 0;
}

推荐答案

newWord[k]

newWord 字符串的大小为零.未定义在 std :: string 末尾进行索引的行为.

The size of the newWord string is zero. The behavior of indexing beyond the end of a std::string is not defined.

您可能需要调整字符串的大小，因此:

You may need to resize the string, thus:

newWord.resize(5);

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