java - 循环结构，很困惑

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You will take int two length of the side of a rectangle (n * m). You will then use a number of the character ‘O’ to print a rectangle to the screen.

The rectangle will be n ‘O’ in one side and m ‘O’ in other side. So id the user enters 4(col) and 3(row), the rectangle should look like:

OOOO

OOOO

OOOO

1. Declare 2 variables: 1 for the number of row, and 1 for the number of col.

2. Prompt the user to input the number of row and the number of col.

3. Use loops (Hint: consider nest loops) to display the rectangle.

Note : You do not have to follow a particular input/output format, but I should be able to understand how to use and understand your program before looking at the code

Note: Don’t forget input validation! What’s a valid value for a row or a col?

Note: Does your program has the input limitation? (e.g. the range of input?)

到目前为止我所拥有的:

public static void main(String[]args){

    int row;
    int column;

    Scanner input = new Scanner(System.in);


    System.out.print("Please enter an integer (row) greater than 0 and less than 15: ");
    row = input.nextInt();

    System.out.print("Please enter an integer (column) greater than 0 and less than 15: ");
    column = input.nextInt();

Answer 1

您应该尝试解决自己的问题，因为学习经历的一部分很困难，但如果它可以帮助您学习，这里是带有一些注释的代码。

        int row = 0;
        int column = 0;

        Scanner input = new Scanner(System.in);
        boolean nonValid = true; //if nonvalid is true the user input is wrong
        while (nonValid) { // keep asking user for input until it is according to your requirements
            System.out.print("Please enter an integer (row) greater than 0 and less than 15: ");
            row = input.nextInt();
            System.out.print("Please enter an integer (column) greater than 0 and less than 15: ");
            column = input.nextInt();
            if (row > 0 && row < 15 && column > 0 && column < 15) {//check user input here if it is good change nonValid to false to exit loop
                nonValid = false;
            } else {
                System.out.println("Bad Input try again!");
            }
        }
        for (int i = 0; i < row; i++) {//this loops rows
            for (int j = 0; j < column; j++) {//this loops columns
                System.out.print("O");//use print as you need each "O" next to each other in a row
            }//
            System.out.println("O");//after each row is printed use println(new line) to move to next line
        }