使用strlen的錯誤

Question

我一直在查找有關如何使strlen工作的示例和教程，但沒有任何工作。我正在製作一個小程序，讓你輸入你的句子，你可以在句子中搜索一個特定的字母。

錯誤讀取：

19:23: error: cannot convert âstd::string {aka std::basic_string<char>}â to âconst char*â for argument â1â to âsize_t strlen(const char*)â

#include <iostream> 
#include <string> 
#include <cstring> 

using namespace std; 

int main() { 
    char letter; 
    string sentence; 
    int count; 

    cout << "Enter a character to count the number of times it is in a sentence: "; 
    cin >> letter; 

    cout << "Enter a sentence and to search for a specified character: " << endl; 
    getline(cin, sentence); 

    for(int i = 0; i < strlen(sentence); i++){ 
      if(sentence[i] == letter){ 
        count++; 
      } 
    } 
    cout << letter << " was found " << count << " times." << endl; 
} 

Answer 1

由於sentence是std::string，你應該使用sentence.length()或strlen(sentence.c_str())。