70，哪里错了？

#include<iostream>
using namespace std;
int main(){
	int n;
	cin>>n;
	char c = 'A';
	bool a[101];
	string b[101];
	string s1 = "ABCDEFGHIJKLMNOPQRSTLVWXYZ";
	for(int i = 0; i < 26; i++){
		a[i] = false;
	}
	int i = 0;
	for(int i = 1; i <= n; i++){
		cin>>b[i];
	}
    string s;
    cin>>s;
    int len = s.length();
    for(int i = 1; i <= n; i++){
    	if(s[0] == b[i][0]){
    		bool flag = true;
    		for(int j = 0; j < len; j++){
    			if(s[j] != b[i][j]){
    				flag = false;
				}
			}
			if(flag == true){
				int l = b[i][len] - 65;
				a[l] = true;
			}
		}
	}
	cout<<"***";
	for(int i = 4; i <= 29; i++){
		if(a[i - 4] == true){
			cout<<s1[i - 4]; 
		}else{
			cout<<"*";
		}
		if(i % 8 == 0){
			cout<<endl;
		}
	}
	cout<<"***";
	return 0; 
}