5/6課輔-字串搜尋

//字串搜尋
#include <iostream>
#include <iostream>
using namespace std;

int main()
{
    string s1="this is s1",s2="is";
    int target=s1.find(s2);
    if(target==string::npos)
        cout<<"can't find\n";
    else
        cout<<"first is at "<<target<<endl;
    return 0;
}