C :

#include <stdio.h>
void main()
{
	int x,p;
	scanf("%d",&x);
	if(x>=90)
	{
		p=x*3;
	}else if(x>=80&&x<90){
		p=x*2;
	}else if(x>=70&&x<80){
		p=x;
	}else{
		p=50;
	}
	printf("%d",p);
	  
}

C++ :

#include <iostream>
using namespace std;
 
int main(){
	//s代表成绩（score），m代表零花钱的金额（money） 
	int s,m;
	cin>>s;
	//判断各个分支
	if(s >= 90){
		m = s * 3;
	} else if(s >= 80 && s < 90){
		m = s * 2;
	} else if(s >= 70 && s < 80){
		m = s;
	} else{
		m = 50;
	}
	
	cout<<m<<endl;
}

Pascal :

var a:longint;
begin
read(a);
if a>=90 then write(a*3);
if (a<90) and (a>=80) then write(a*2);
if (a<80) and (a>=70) then write(a);
if a<70 then write('50');
end.

Java :

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int s = 0 ;
		if(a>=90) {
			s = a * 3 ;
			System.out.println(s);
		}else if(a>=80 && a<90) {
			s = a * 2 ;
			System.out.println(s);
		}else if(a>=70 && a<80) {
			s = a ;
			System.out.println(s);
		}else {
			System.out.println(50);
		}
	}
}

Python :

n=int(input())
if n>=90:
    print(n*3)
elif n>=80 and n<90:
    print(n*2)
elif n>=70 and n<80:
    print(n)
else:
    print(50)