자바 for 반복문 구구단예제

package loop;
//dan을 입력받아서 구구단 출력
import java.util.Scanner;

public class ForExam03 {

	public static void main(String[] args) {
/*
		출력형태) 2단
				  -----------------
				  2*1=2
				  2*2=4
				  ...
				  2*9=18
				  -----------------
*/
		int dan = 2;
		int sum = 0;
		Scanner scan = new Scanner(System.in);
		
		System.out.print("출력할 단 입력>>");
		dan = scan.nextInt();
		System.out.println(dan+"단");
		System.out.println("-----------------");
		
		for(int i=1;i<=9;i++) {
			sum = dan * i;
			System.out.println(dan+"*"+i+"="+sum);
		}
		System.out.println("-----------------");
		
	}//end of main

}//end of class

결과

---

System.out.printf(); 사용하기

package loop;
//dan을 입력받아서 구구단 출력
import java.util.Scanner;

public class ForExam03 {

	public static void main(String[] args) {
/*
		출력형태) 2단
				  -----------------
				  2*1=2
				  2*2=4
				  ...
				  2*9=18
				  -----------------
*/
	
		int dan = 2;
		int sum = 0;
		Scanner scan = new Scanner(System.in);
		
		System.out.print("출력할 단 입력>>");
		dan = scan.nextInt();
		System.out.println(dan+"단");
		System.out.println("-----------------");
		
		for(int i=1;i<=9;i++) {
			sum = dan * i;
			System.out.printf("%d * %d = %2d \n", dan, i, sum);
		}
		System.out.println("-----------------");
		
		

	}//end of main

}//end of class

결과

---

package loop;

public class ForExam04 {

public static void main(String[] args) {

		//구구단 출력
		
		for(int i=2; i<=9; i++) {
		System.out.println("-------------");
		
		for(int j=1; j<=9; j++) {

		System.out.println(i + " * " + j + " = " + (i*j));
				
		}//안쪽 for의 끝
		
		}//밖 for의 끝
		
		System.out.println();
		System.out.println("***************************");
		
		for(int i=2; i<=9; i++) { 
		
		for(int j=1; j<=9; j++) {
		
		// System.out.print(i + " * " + j + " = " + (i*j) + "\t");
		System.out.printf("%d * %d = %2d \t", i, j, i*j);
		
		}//안쪽 for의 끝
		
		System.out.println();

		}//밖 for의 끝


	}//end of main

 

}//end of class

결과