The problem
Write a program that prompts the user to enter an integer from 1 to 15 and displays a pyramid.
Breaking it down
public static void main(String[] strings) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of lines (1-15): ");
int numberOfLines = input.nextInt();
input.close();
while (numberOfLines < 1 || numberOfLines > 15) {
System.out.println("Invalid input");
System.out.print("Enter the number of lines (1-15): ");
numberOfLines = input.nextInt();
}
for (int currentRow = 1; currentRow <= numberOfLines; currentRow++) {
for (int currentColumn = 1; currentColumn <= numberOfLines
* currentRow; currentColumn++) {
System.out.printf("%3s", " ");
}
for (int number = currentRow; number >= 1; number--) {
System.out.printf("%3d", number);
}
for (int number = 2; number <= currentRow; number++) {
System.out.printf("%3d", number);
}
System.out.println();
}
}Output
Enter the number of lines (1-15): 15
1
2 1 2
3 2 1 2 3
4 3 2 1 2 3 4
5 4 3 2 1 2 3 4 5
6 5 4 3 2 1 2 3 4 5 6
7 6 5 4 3 2 1 2 3 4 5 6 7
8 7 6 5 4 3 2 1 2 3 4 5 6 7 8
9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9
10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10
11 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 11
12 11 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 11 12
13 12 11 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 11 12 13
14 13 12 11 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 11 12 13 14
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15