C++ STD 字符串擦除

Question

我做了一个从句子中删除单词的小程序。每次我尝试运行程序时，它都会给我这些错误

错误 2 错误 C2040：“==”：“int”的间接级别不同 来自 'const char [4]' c:\program files (x86)\microsoft visual studio 12.0\vc\include\xutility line:3026 column:1 STL string erase

和

错误 1 ​​错误 C2446：“==”：没有从“const char *”转换为 'int' c:\program files (x86)\microsoft visual studio 12.0\vc\include\xutility line:3026 column:1 STL string erase

这也是我的代码

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main(){
    string sample("hello world");
    cout << "The sample string is: ";
    cout << sample << endl;
    //erasing world
    cout << "Erasing world" << endl;
    sample.erase(5, 10);
    cout << sample << endl;
    //finding h and erasing it
    string::iterator iCharH = std::string::find(sample.begin(), sample.end(), "h");
    cout << "finding h and erasing it" << endl;
    if (iCharH != sample.end()){
        sample.erase(iCharH);
    }
    cout << sample << endl;
    //erasing entirely
    sample.erase(sample.begin(), sample.end());
    if (sample.length() == 0){
        cout << "The string is empty" << endl;
    }
    system("pause");
    return 0;
}

Answer 1

你需要的是std::string::find，正如克里斯在评论中所写的那样。原因基本上是您希望删除单词，而不是单个字符。

Answer 2

我认为对std::string::erase 和std::string::find 成员函数存在误解。我在上面的评论中列出的参考资料是否有帮助，为了清楚起见，在此重复：std::basic_string::find 和 std::basic_string::erase？

使用这三到四个修改，它应该可以解决问题。请注意，上面帖子中的所有代码都重复了修改和额外的 cmets，以便将所有代码放在一个位置以供将来查看。

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main(){
    string sample("hello world");
    cout << "The sample string is: ";
    cout << sample << endl;
    //erasing world
    cout << "Erasing world" << endl;

    //
    // Erase the word "world" from the string, while not sending erase more
    // characters to erase than going past the end of the string.
    // erase is friendly enough not to have issues with passing a higher count
    // in the second parameter, but future C++ versions could throw an exception
    // in some future standard, e.g. C++14 or later.
    //
    sample.erase(5, 6);
    cout << sample << endl;

    //finding h and erasing it
    //
    // Use the short version of the find member function to look for the string
    // "h".  iCharH is now declared as in int, instead of an iterator.  If the 
    // search string is not present, the iCharH value will be std::string::npos,
    // otherwise iCharH will contain the starting index position of the search
    // string.
    //    string::iterator iCharH = std::string::find(sample.begin(), sample.end(), "h");
    //
    int iCharH = sample.find("h");
    cout << "finding h and erasing it" << endl;

    //
    // Using a different overloaded form of erase, make sure to remove the 
    // exact number of characters.  In this case, the number is ONE.  The
    // std::string::npos can be shortened to string::npos, but only because
    // using namespace std; is above.
    //
    if (iCharH != std::string::npos){
        sample.erase(iCharH, 1);
    }
    cout << sample << endl;
    //erasing entirely

    //
    // Passing no parameters to erase empties a string.  This is optional, but
    // less typing than the iterator version.  The iterator version works 
    // perfectly too.
    //    sample.erase(sample.begin(), sample.end());
    //
    sample.erase();
    if (sample.length() == 0){
        cout << "The string is empty" << endl;
    }

    system("pause");
    return 0;
}