C++ :

#include<iostream>
using namespace std;
int main(){
	float a;
	cin>>a;
	if(a>30.0)
	cout<<"开空调";
	else cout<<"不开空调";
	return 0;
}

Python :

# coding=utf-8
a=float(input())
if a>30:
    print("开空调")
else:
    print("不开空调")