使用升序和降序数字在Java中打印居中金字塔

Question

I'm trying to print a centered pyramid of 2^n, where 2^row# is the centered number of each row, the numbers to the left are ascending to 2^row# and the numbers to the right are descending. I'm pretty new to Java and it took me a really long time to get this much. But now I'm stuck. The last row is the only row that is correct. I don't know how to make it so 64 is not printed on every line. Can anyone please give me a hint?

I've tried messing with every single parameter - starting the last loop with the first row, the last row, changing the starting power, etc. and I just can't figure it out.

Thank you for any hints!

public static void main (String [] args){

    int row;
    for (row = 0; row <= 8; row++){ // Prints each row 
        for (int spaces = 8; spaces >= row; spaces --){ // Prints out spaces to left
            System.out.print("  ");
        }

        int power1 = 0; // Power that 2 is being raised to
        for (int i = 0; i < row; i++) { // Prints left side of the pyramid 
            System.out.print(" " + (int)Math.pow(2, power1));
            power1++;
        }

        int power2 = 7;
        for (int i = 1; i < row; i++) { // Prints right side of the pyramid 
            power2--;
            System.out.print(" " + (int)Math.pow(2, power2));       
        }

        System.out.println();
    }       
  }
}

Answer 1

Your problem lies in the fact you always start the right side of the pyramid at 2^7, since you hard code the power2 = 7 decleration and assignment. If you start this value instead at the current row - 1, you get the behavior you're looking for. Code:

public static void main (String [] args){

int row;
for (row = 0; row <= 8; row++){ // Prints each row 
    for (int spaces = 8; spaces >= row; spaces --){ // Prints out spaces to left
        System.out.print("  ");
    }

    int power1 = 0; // Power that 2 is being raised to
    for (int i = 0; i < row; i++) { // Prints left side of the pyramid 
        System.out.print(" " + (int)Math.pow(2, power1));
        power1++;
    }

    int power2 = row - 1;
    for (int i = 1; i < row; i++) { // Prints right side of the pyramid 
        power2--;
        System.out.print(" " + (int)Math.pow(2, power2));       
    }

    System.out.println();
}

Answer 2

This part is not right.

        int power2 = 7;
    for (int i = 1; i < row; i++) { // Prints right side of the pyramid 
        power2--;
        System.out.print(" " + (int)Math.pow(2, power2));       
    }

On row 2 you get power2=6 so you display 2^6=64.

You should instead be doing something like

        int power2 = power1;  
    for (int i = 1; i < row; i++) { // Prints right side of the pyramid 
        power2--;
        System.out.print(" " + (int)Math.pow(2, power2));       
    }

Answer 3

You are assigning constant to power2 instead of depending value on row. Can you try this please.

int power2 = row-1;