if, switch 연습(성적구하기)

문제 이름(name),국어(kor),영어(eng),수학(math)점수를 입력받아서  총점(tot),평균(avg), 학점(grade)을 구하시오 평균이 90이상이면 'A'학점 평균이 80이상이면 'B'학점 평균이 70이상이면 'C'학점 평균이 60이상이면 'D'학점 그외는 'F'학점 [실행결과] 이름 입력 :  홍길동  국어 입력 : 78   영어 입력 : 89   수학 입력 : 100  *** 홍길동 성적 *** 국어      영어      수학      총점      평균      학점 78        89          100      xxxx       xx.xxx     x

1. if문 사용

 	package if_Ex;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class SungJuk {
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		
		int kor, eng, math;
		String name;
		char grade;
		
		System.out.print("이름 입력 : ");
		name = br.readLine();
		System.out.print("국어 입력 : ");
		kor = Integer.parseInt(br.readLine());
		System.out.print("영어 입력 : ");
		eng = Integer.parseInt(br.readLine());
		System.out.print("수학 입력 : ");
		math = Integer.parseInt(br.readLine());
		
		int sum = kor + eng + math;
		double avg = sum/3.0;
		//int avg = (int)(sum/3.0);
		
		if(avg>=90) {
			grade ='A';
		}else if(avg>=80) {
			grade ='B';
		}else if(avg>=70) {
			grade ='C';
		}else if(avg>=60) {
			grade ='D';
		}else {
			grade = 'F';
		}
	
		System.out.println("[실행결과]");
		System.out.println("\t***"+name+"성적 ***");
		System.out.println("국어\t영어\t수학\t총점\t평균\t학점");
		System.out.println(kor+"\t"
						  +eng+"\t"
						  +math+"\t"
						  +sum+"\t"
						  +String.format("%.3f", avg)+"\t"
						  +grade);

	}

}

2. switch 사용

package if_Ex;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class SungJuk {
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		
		int kor, eng, math;
		String name;
		char grade;
		
		System.out.print("이름 입력 : ");
		name = br.readLine();
		System.out.print("국어 입력 : ");
		kor = Integer.parseInt(br.readLine());
		System.out.print("영어 입력 : ");
		eng = Integer.parseInt(br.readLine());
		System.out.print("수학 입력 : ");
		math = Integer.parseInt(br.readLine());
		
		int sum = kor + eng + math;
		double avg = sum/3.0;
		//int avg = (int)(sum/3.0);

		switch((int)avg/10) {
		//avg를 int로 변환하고 10으로 나눈 값들을 이용.
		case 10:
		case 9: grade = 'A';
			break;
		case 8:	grade = 'B';
			break;
		case 7:	grade = 'C';
			break;
		case 6:	grade = 'D';
			break;
		default :
			grade = 'F';
		}
		System.out.println("[실행결과]");
		System.out.println("\t***"+name+"성적 ***");
		System.out.println("국어\t영어\t수학\t총점\t평균\t학점");
		System.out.println(kor+"\t"
						  +eng+"\t"
						  +math+"\t"
						  +sum+"\t"
						  +String.format("%.3f", avg)+"\t"
						  +grade);

	}

}