C :

#include<stdio.h>
int main(){
char c;
int score;
scanf("%d",&score);
if(score>=90)
  c='A';
else if(score>=80&&score<=89)
  c='B';
else if(score>=70&&score<=79)
  c='C';
else if(score>=60&&score<=69)
  c='D';
else if(score<60)
  c='E';
printf("%c\n",c);
  return 0;
  }

C++ :

#include <stdio.h>
int main() {
	int score;
	char level;
	scanf("%d", &score);
	if (score >= 90)
		level = 'A';
	else if (score >= 80)
		level = 'B';
	else if (score >= 70)
		level = 'C';
	else if (score >= 60)
		level = 'D';
	else
		level = 'E';
	printf("%c\n", level);
	return 0;
}

Pascal :

var n:longint;
begin
  readln(n);
  if n>=90 then writeln('A')
    else if n>=80 then writeln('B')
      else if n>=70 then writeln('C')
        else if n>= 60 then writeln('D')
         else if n>0 then writeln('E');
end.    
    

Java :

import java.util.*;
public class Main {
	public static void main(String args[]) {
		Scanner cin = new Scanner(System.in);
		char c;
		int x;
		x=cin.nextInt();
		if(x<60)
			c='E';
		else if(x<70)
			c='D';
		else if(x<80)
			c='C';
		else if(x<90)
			c='B';
		else
			c='A';
		System.out.println(c);
	}
}

Python :

x = input()
if x >= 90:
  print 'A'
elif 80 <= x < 90:
  print 'B'
elif 70 <= x < 80:
  print 'C'
elif 60 <= x < 70:
  print 'D'
else:
  print 'E'