根据成绩返回等级-if与switch实现

package com.majing;

public class GradeRank {

public static void main(String[] args) {
// TODO Auto-generated method stub

//		//rank1 test ————————————————————
//		//边界值
//		float grade = 99f;
//		System.out.println(rank1(grade));
//		grade = 100f;
//		System.out.println(rank1(grade));
//		grade = 101f;
//		System.out.println(rank1(grade));
//		grade = -1f;
//		System.out.println(rank1(grade));
//		grade = 0f;
//		System.out.println(rank1(grade));
//		grade = 1f;
//		System.out.println(rank1(grade));
//		//语句覆盖
//		grade = 65f;
//		System.out.println(rank1(grade));
//		grade = 72f;
//		System.out.println(rank1(grade));
//		grade = 83f;
//		System.out.println(rank1(grade));
//		grade = 95f;
//		System.out.println(rank1(grade));
//		grade = 51f;
//		System.out.println(rank1(grade));
//
//rank2 test ————————————————————
//边界值
int grade2 = 99;
System.out.println(rank1(grade2));
grade2 = 100;
System.out.println(rank1(grade2));
grade2 = 101;
System.out.println(rank1(grade2));
grade2 = -1;
System.out.println(rank1(grade2));
grade2 = 0;
System.out.println(rank1(grade2));
grade2 = 1;
System.out.println(rank1(grade2));
//语句覆盖
grade2 = 65;
System.out.println(rank1(grade2));
grade2 = 72;
System.out.println(rank1(grade2));
grade2 = 83;
System.out.println(rank1(grade2));
grade2 = 95;
System.out.println(rank1(grade2));
grade2 = 51;
System.out.println(rank1(grade2));
}

//if实现
public static char rank1(float grade){
char result = 0;
if(grade < 0 || grade > 100){
System.out.println("Illegal input");
}else if(grade >= 90){
result = 'A';
}else if(grade >= 80){
result = 'B';
}else if(grade >= 70){
result = 'C';
}else if(grade >= 60){
result = 'D';
}else{
result = 'E';
}
return result;
}

//switch 实现
public static char rank2(int grade){
int tenDigit = grade/10;
char result = 0;
switch (tenDigit){
case 10:
case 9:
result = 'A';
break;
case 8:
result = 'B';
break;
case 7:
result = 'C';
break;
case 6:
result = 'D';
break;
default:
if(tenDigit >= 0 && tenDigit < 6){
result = 'E';
}else{
System.out.println("Illegal Input");
}
}
return result;
}
}