根据用户输入在Java中打印菱形

用户输入正整数，否则程序会提示用户，直到他们输入

您需要循环扫描

do{    userInput = keyboard.nextInt();     if (userInput % 2 == 0)        System.out.println("That is not an Odd Integer!");     if(userInput < 0)        System.out.println("That is not a Positive Odd Integer");} while(userInput < 0 || userInput %2 == 0);

现在您可以删除该验证

else if (userInput%2 == 1){

现在，我在检查循环时意识到的第一件事是

if (row+col==userInput-1 || )

请注意，您可以替换为

System.out.print("n");

System.out.println("")

现在替换循环条件，使它们从0开始

for (int row = 0; row <= userInput; row++){        for (int col = 0; col <= userInput; col++ ){

现在，由于您想要钻石，因此需要有4个对角线，因此需要2个循环（一个用于顶部和底部）。

for (int i = 1; i < userInput; i += 2)//Draw the top of the diamond{    for (int j = 0; j < userInput - 1 - i / 2; j++)//Output correct number of spaces before    {        System.out.print(" ");    }    for (int j = 0; j < i; j++)//Output correct number of asterix    {        System.out.print("*");    }    System.out.print("n");//Skip to next line}for (int i = userInput; i > 0; i -= 2)//Draw the bottom of the diamond{    for (int j = 0; j < userInput -1 - i / 2; j++)    {        System.out.print(" ");    }    for (int j = 0; j < i; j++)    {        System.out.print("*");    }    System.out.print("n");}

所以最终的代码看起来像这样

public static void main(String[] args){    Scanner keyboard = new Scanner(System.in);    System.out.println("Welcome to the drawing program:");    System.out.println("Please Input a Positive Odd Integer:");    char userAnswer;    int userInput;    do    {        userInput = keyboard.nextInt();        if (userInput % 2 == 0)        { System.out.println("That is not an Odd Integer!");        }        if (userInput < 0)        { System.out.println("That is not a Positive Odd Integer");        }    } while (userInput < 0 || userInput % 2 == 0);    for (int i = 1; i < userInput; i += 2) //This is the number of iterations needed to print the top of diamond (from 1 to userInput by step of two for example with 5 = {1, 3, 5} so 3 rows.    {        for (int j = 0; j < userInput - 1 - i / 2; j++)//write correct number of spaces before, example with 5 = j < 5 - 1 -i / 2, so it would first print 4 spaces before, with 1 less untill it reach 0        {System.out.print(" ");//write a space        }        for (int j = 0; j < i; j++)        { System.out.print("*");//write an asterix        }        System.out.println("");    }    // Same logic apply here but backward as it is bottom of diamond    for (int i = userInput; i > 0; i -= 2)    {        for (int j = 0; j < userInput -1 - i / 2; j++)        { System.out.print(" ");        }        for (int j = 0; j < i; j++)        { System.out.print("*");        }        System.out.print("n");    }}