[Java] 반복문 문제

자바 반복문 문제

구구단 

while 문

import java.util.Scanner;

public class Main {

       public static void main(String[] args) {

              Scanner sc = new Scanner(System.in);

              

              int num = sc.nextInt();

              int i =1;

              

              while(i < 10) {

                     System.out.println(num +" * " + i + " = " + (num*i));

                     i++;

              }

              

              sc.close();

       }

}

for 문

import java.util.Scanner;

public class HelloWorld {

       public static void main(String[] args) {

              Scanner sc = new Scanner(System.in);            

              System.out.print("숫자 입력 :");

              int num = sc.nextInt();                         

              for(int i = 1; i < 10; i++) {

                     System.out.println(num +" * " + i + " = " + (num*i));

              }

              

              sc.close();

       }

}

문제

1에서 20까지 의 수에서 2의배수와 5의 배수를 제외한 숫자 출력

for문

public class HelloWorld {

       public static void main(String[] args) {

                     

              for(int i = 1; i < 21; i++) {

                     if(i % 2 ==0 || i % 5 == 0) {

                           continue;

                     }

                     System.out.println(i);

              }

              

              

       }

}

* 로 삼각형 만들기

for문

public class HelloWorld {

       public static void main(String[] args) {               

              for(int i = 0; i < 5; i++) {

                     for(int j = 0; j <= i; j++) {

                           System.out.print("*");

                     }

                     System.out.println();

              }

       }

}

역 삼각형

public class HelloWorld {

       public static void main(String[] args) {               

              for(int i = 0; i < 5; i++) {

                     for(int j = 5; j > i; j--){

                           System.out.print("*");

                     }

                     System.out.println();

              }

       }

}