2015.09.09 C++笔记

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

int count( const string &s, char ch, int &index )
{
    index = s.size();
    int counter = 0;
    for (int i = 0; i<s.size()+1; i++)
    {
        if (s[i]==ch)
        {
            if (index == s.size()+1)index = i+1;
            counter++;
        }
    }
    return counter;
}

int main()
{
    //02.返回字符串中某字符的数量和首次出现的位置，若没有则返回0和字符串长度
    string s; char ch;
    cin>>s;
    cin>>ch;
    int counter, index;
    counter = count(s, ch, index);
    cout<<counter<<" "<<index<<endl;

    //01.提示输入密码，如果两次输入不一致则报错。使用try, throw和catch
    string s1, s2;
    try
    {
        cout<<"Please enter password:"<<endl;
        cin>>s1;
        cout<<"\nPlease enter again:"<<endl;
        cin>>s2;
        if (s1 != s2)
            throw runtime_error("wrong password!");
    }
    catch (runtime_error err)
    {
        cerr<<err.what()<<endl;
    }

    cin>>s1;
    return 0;
}