[Java] 이중 for문을 사용하여 별 찍기

1. 2차원 기본 별 찍기

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		
		Scanner sc =new Scanner(System.in);
		System.out.print("정수를 입력해 주세요 : ");
		int num = sc.nextInt();
		
		for(int i = 0 ; i < num; i++) {
			for(int j = 0; j<num; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
		sc.close();
		      }

	}

2. 직각삼각형 별(왼쪽) 찍기

 

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		
		Scanner sc =new Scanner(System.in);
		System.out.print("정수를 입력해 주세요 : ");
		int num = sc.nextInt();
		
		for(int i=0 ; i<num+1; i++) {
			for(int j=0; j<i; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
		sc.close();
		      }

	}

3. 직각삼각형 별(오른쪽) 찍기

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		System.out.print("정수를 입력하세요 : ");
		Scanner scanner = new Scanner(System.in);
		
		int num = scanner.nextInt();		
		
		for(int i=0; i<num; i++) {
			for(int j=0; j<num-i ; j++) {
				System.out.print(" ");
			}
			for(int j=0 ; j<i+1 ; j++) {
				System.out.print("*");
				
				
			}System.out.println();
		}
	}
}

4. 역 직각삼각형 별(왼쪽) 찍기

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		System.out.print("정수를 입력하세요 : ");
		
		Scanner sc = new Scanner(System.in);
		int num = sc.nextInt();
		
		String str = "";
		
		for(int i = num; i > 0 ; i--){
			for (int j = 0 ; j < i; j++) {
				str +="*";
				System.out.print(" ");
			}
		
			System.out.printf("%"+num+"s",str);		
			System.out.println();
			str = "";
		}
	}
}

5. 역 직각삼각형 별(오른쪽) 찍기

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		System.out.print("정수를 입력하세요 : ");
		
		Scanner sc = new Scanner(System.in);
		int num = sc.nextInt();
	   
	      for(int i = 0; i < num ; i++)
	      {
	         for (int j = 0 ; j < i; j++) 
	         {
	            System.out.print(" ");
	         }
	         for(int k= num; k>i ; k--) 
	         {
	            System.out.print("*");
	         }
	                  
	         System.out.println();
	      }
	}
}

6. 피라미드 별 찍기

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		System.out.print("정수를 입력하세요 : ");
		
		int num =0;
		Scanner scanner = new Scanner(System.in);
		
		num = scanner.nextInt();
		
		for(int i = 0; i<num; i++) {
			for(int j = num-i-1; j>0; j--) {
				System.out.print(" ");
			}
			for(int k=0; k<i*2+1; k++) {
				System.out.print("*");
			}
			System.out.println();
		}

	}
}

7. 역 피라미드 별 찍기

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		System.out.print("정수를 입력하세요 : ");
		Scanner scanner = new Scanner(System.in);
		
		int num = scanner.nextInt();
		
		
		for(int i=0; i<num; i++) {
			for(int j=0; j<i+1 ; j++) {
				System.out.print(" ");
			}
			for(int k=(num-i)*2-1 ; k>0 ; k--) {
				System.out.print("*");
				
				
			}System.out.println();
		}
	}
}

8. 다이아몬드 별찍기 (단, 정수를 입력할때 홀수만 받음)

import java.util.Scanner;
public class asdasdasd {

	public static void main(String[] args) {
		System.out.print("정수를 입력하세요 : ");		
		
		Scanner scanner = new Scanner(System.in);
		int num = scanner.nextInt();
		
		if(num%2!=0) {
		
		for(int i = 0; i<num; i++) {
			for(int j=num-i-1; j>0; j--) {
				System.out.print(" ");
			}
			for(int k=0; k<i*2+1; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		for(int i=0; i<num; i++) {
			for(int j=0; j<i+1 ; j++) {
				System.out.print(" ");
			}
			for(int k=(num-i-1)*2-1 ; k>0 ; k--) {
				System.out.print("*");
				
				
			}System.out.println();
		}
		
		}
		scanner.close();
	}	
}

9. 삼각형 (오른쪽) 찍기(단, 정수를 입력할때 홀수만 받음)

System.out.print("정수를 입력하세요 : ");
		int num=0;
		Scanner scanner = new Scanner(System.in);
		num = scanner.nextInt();
		
		if(num%2!=0) {
			for(int i = 0; i<num+1; i++) {
				for(int j = 0; j < i; j++) {
					System.out.print("*");
				}
				System.out.println();
			}
			for(int i = 0; i<num+1; i++) {
				for(int j = num-1; j > i; j--) {
					System.out.print("*");		
				}
				System.out.println();
			}
		}
		scanner.close();