백준 2438, 2439번 - 별찍기1,2 + 그외의 다양한 패턴 만들기

[별찍기1]

import java.util.Scanner;

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

 

• 외부 for문을 통해서 몇줄 반복할지
• 내부 for문을 통해서 "*"을 얼마나 반복할지

[별찍기2]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int m = n;
		
		for(int i = 1; i <= n; i++) {
			for(int j = m; j > i; j--) {
				System.out.print(" ");
			}
			for(int k = 1; k <= i; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		sc.close();
	}
}

 

• 내부 첫번째 for문을 통해서 " "를 얼마나 반복할지
• 내부 두번째 for문을 통해서 "*"을 얼마나 반복할지

[별찍기3]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int m = n;

		for (int i = 1; i <= n; i++) {
			for (int j = m - i; j >= 0; j--) {
				System.out.print("*");
			}
			System.out.println();
		}
		sc.close();
	}
}

 

• 내부 for문을 통해 "*"을 얼마나 반복할지
•  줄은 늘어나고 그에 비례하게 * 개수를 줄여야하니까 고정된 m값에서 i를 뺌

[별찍기4]

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int m = n;

		for (int i = 1; i <= n; i++) {
			for (int j = 1; j < i; j++) {
				System.out.print(" ");
			}
			for (int k = m - i; k >= 0; k--) {
				System.out.print("*");
			}
			System.out.println();
		}
		sc.close();
	}
}

 

• 내부 첫번째 for문을 통해 " "를 얼마나 반복할지(늘어나야 하니까 ++)
• 내부 두번째 for문을 통해 "*"을 얼마나 반복할지(줄 수에 맞게 *입력)

[별찍기5]

 

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		for(int i = 1; i <= n; i++) {
			for(int j = i; j < n; j++) {
				System.out.print(" ");
			}
			for(int k = 0; k < 2 * i - 1; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
        sc.close();
	}
}

 

[별찍기6]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();

		for(int i = 1; i <= n; i++) {
			for(int j = 1; j < i; j++) {
				System.out.print(" ");
			}
			for(int k = 1; k <= 2 * n - (2 * i - 1); k++) {
				System.out.print("*");
			}
			System.out.println();
		}
        sc.close();
	}
}

 

[별찍기7]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		for(int i = 0; i < n; i++) {
			for(int k = 0; k <= i ; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
		for(int i = 1; i < n; i++) {
			for(int k = i; k < n; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
        sc.close();
	}
}

 

[별찍기8]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		for(int i = 0; i < n; i++) {
			for(int k = i; k < n; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
		for(int i = n-1; i >= 1; i--) {
			for(int k = 0; k < n-i+1 ; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
        sc.close();
	}
}

[별찍기9]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		for(int i = 1; i <= n; i++) {
			for(int j = n; j > i; j--) {
				System.out.print(" ");
			}
			for(int k = 0; k < i ; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
		for(int i = 1; i < n; i++) {
			for(int j = 1; j <= i; j++) {
				System.out.print(" ");
			}
			for(int k = i; k < n; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
        sc.close();
	}
}

 

[별찍기10]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		// 별 증가
		for(int i = 1; i <= n; i++) {
			for(int j = i; j < n; j++) {
				System.out.print(" ");
			}
			for(int k = 0; k < 2 * i - 1; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
		// 별 감소
		for(int i = 1; i <= n - 1; i++) {
			for(int j = 0; j < i; j++) {
				System.out.print(" ");
			}
			for(int k = 0; k < 2 * n - (2 * i + 1); k++) {
				System.out.print("*");
			}
			System.out.println();
		}
        sc.close();
	}
}

 

[별찍기11]

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int m = n;
		
		for(int i = 1; i <= n; i++) {
			for(int k = m; k >= i ; k--) {
				System.out.print("*");
			}
			for(int j = 1; j <= 2 * i - 1; j++) {
				System.out.print(" ");
			}
			for(int k = m; k >= i ; k--) {
				System.out.print("*");
			}
			System.out.println();
		}
		
		int a = n;
		for(int i = 1; i < n; i++) {
			for(int k = 0; k <= i ; k++) {
				System.out.print("*");
			}
			for(int j = 0; j < 2 * (a - i) - 1; j++) {
				System.out.print(" ");
			}
			for(int k = 0; k <= i ; k++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
        sc.close();
	}
}