[Java] 8. 조건문_1.if-else문

Ex. 짝수와 홀수 구분하기

package ex03;

// 클래스명 = 파일명과 동일
// 클래스명 규칙 = 파스칼 표기법 (단어별 첫글자는 대문자)

import java.util.Scanner;

public class EvenOdd {
    public static void main(String[] args) {
        int number;

        Scanner sc = new Scanner(System.in);
        System.out.println("정수를 입력하시오: ");
        number = sc.nextInt();

        if (number % 2 == 0) {
            System.out.println("입력된 정수는 짝수입니다.");
        } else {
            System.out.println("입력된 정수는 홀수입니다.");
        }

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=51754:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\java_lec\study\out\production\study ex03.EvenOdd
정수를 입력하시오: 
4
입력된 정수는 짝수입니다.

Process finished with exit code 0

다중 if-else 문

Ex. 사용자로부터 받은 정수가 양수인지, 0인지, 음수인지 검사해보기

package ex03;

import java.util.Scanner;

public class Nested {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        System.out.println("정수를 입력하시오: ");
        int number = sc.nextInt();

        if (number > 0) {
            System.out.println("양수입니다.");
        } else if (number == 0) {
            System.out.println("0입니다.");
        } else {
            System.out.println("음수입니다.");
        }

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=51772:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\java_lec\study\out\production\study ex03.Nested
정수를 입력하시오: 
3
양수입니다.

Process finished with exit code 0

Ex. 성적 처리 예제

package ex03;

import java.util.Scanner;

public class Grading {
    public static void main(String[] args) {
        int grade;

        Scanner sc = new Scanner(System.in);
        System.out.println("성적을 입력하시오: ");
        grade = sc.nextInt();

        if (grade >= 90) {
            System.out.println("학점 A");
        } else if (grade >= 80) {
            System.out.println("학점 B");
        } else if (grade >= 70) {
            System.out.println("학점 C");
        } else if (grade >= 60) {
            System.out.println("학점 D");
        } else System.out.println("학점 F");
    }

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=51780:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\java_lec\study\out\production\study ex03.Grading
성적을 입력하시오: 
70
학점 C

Process finished with exit code 0

Ex. 가위, 바위, 보 게임

package ex03;

import java.util.Scanner;

public class RockPaperSicssor {
    final int SCISSOR = 0;
    final int ROCK = 1;
    final int PAPER = 2;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("가위(0), 바위(1), 보(2): ");
        int user = sc.nextInt();

        int computer = (int) (Math.random() * 3);
        if (user == computer) {
            System.out.println("인간과 컴퓨터가 비겼음");
        } else if (user == (computer + 1) % 3) {
            System.out.println("인간: " + user + "컴퓨터: " + computer + "인간 승리");
        } else {
            System.out.println("인간: " + user + "컴퓨터: " + computer + "컴퓨터 승리");
        }

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=51833:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\java_lec\study\out\production\study ex03.RockPaperSicssor
가위(0), 바위(1), 보(2): 

2
인간: 2컴퓨터: 1인간 승리

Process finished with exit code 0

-----------------------------------------------------------------------------------------

C:\workspace\tools\jdk-21\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\lib\idea_rt.jar=51846:C:\Program Files\JetBrains\IntelliJ IDEA 2024.3.2.1\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\workspace\java_lec\study\out\production\study ex03.RockPaperSicssor
가위(0), 바위(1), 보(2): 
1
인간과 컴퓨터가 비겼음

Process finished with exit code 0