0分求助

#include<bits/stdc++.h> 
using namespace std;
int main() 
{
	int n,q,a,b;
	string s,d;
	cin>>n;
	cin>>s;
	while(n--)
	{
		cin>>q;
		if(q==1)
		{
			cin>>d;
			s+=d;
			cout<<s<<endl;	
		}
		else if(q==2)
		{
			cin>>a>>b;
			s=s.substr(a,b);
			cout<<s<<endl;
		}
		else if(q==3)
		{
			cin>>d>>a;
			s.insert(a,d);
			cout<<s<<endl;			
		}
		else if(q==4)
		{
			cin>>d;
			cout<<(int)s.find(d)<<endl;
		}
	}
	return 0;
}