#include<bits/stdc++.h> using namespace std; int main(){ char a,b,c; cin>>a; cout<<" "<<a<<" "<<endl; cout<<" "<<a<<a<<a<<" "<<endl; cout<<a<<a<<a<<a<<a; return 0; } //最简单的办法

s = input()
print("  " + s)
print(" " + s * 3)
print(s * 5)

#include using namespace std; int main(){ char ch; cin>>ch; cout<<" "<<ch<<endl; cout<<" "<<ch<<ch<<ch<<endl; cout<<ch<<ch<<ch<<ch<<ch; }

显而易见，结果就是输出第一行 $1$ 个字符，第二行 $3$ 个字符，第三行 $5$ 个字符。

#include<iostream>
using namespace std;
int main(){
	char ch;
	cin>>ch;
	cout<<"  "<<ch<<endl<<" ";
	cout<<ch<<ch<<ch<<endl;
	cout<<ch<<ch<<ch<<ch<<ch;
}