为什么以下代码过不了而加了endl就过了？

#include <iostream>
using namespace std;
int main(){
	int n;
	cin>>n;
	if(n<100)cout<<"00";
	else if(n<1000)cout<<0<<n/100;
	else if(n<=5000)cout<<n/100;
	else if(n<=30000)cout<<n/1000+50;
	else if(n<=70000)cout<<(n/1000-30)/5+80;
	else cout<<89;
	return 0;
}