W3School TIY Editor

#include <iostream> #include <string> using namespace std; int main() { string myString = "Hello"; cout << "原始字符串: " << myString << "\n"; cout << "第一个字符: " << myString.at(0) << "\n"; cout << "第二个字符: " << myString.at(1) << "\n"; cout << "最后一个字符: " << myString.at(myString.length() - 1) << "\n"; myString.at(0) = 'J'; cout << "修改后的字符串: " << myString; return 0; }