比如定义一个字符串类型为string a;
a="today is sunday";
想把a变为today is sunda，有没有什么快捷的方法？

不知道咋用，我只是想做个密码输入类
class Key
{
    public:
        int cmp()
        {
            
            cout<<setw(30)<<"请输入密码:"<<endl;
            while((ch=_getch())!='\r')
            {
               
                if(ch=='\b')
                {
                    
                    cout<<"\b \b";
                    password.pop_back();
                    continue;
                }
               
                password.push_back(ch);
                cout<<"*";
            }
            if(password==pass)
            return 1;
            else
            return 0;

            
        }
    private:
        char ch;
        vector<char> password;
        vector<char> pass="eb36520";
};