CPP0102-CHỮ HOA – CHỮ THƯỜNG

#include <bits/stdc++.h>
#define endl "\n"
using namespace std;
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t;
	cin>>t;
	while(t--){
		char a;
		cin>>a;
		if(a>='a'&&a<='z') a-=32;
		else a+=32;
		cout<<a<<endl;
	}
}