我如何在Java中使用for循环打印此模式*** +++ ------ +++ ***？

Question

I used this code for the 1st part of the code:

for(int i=0;i<2;i++)
  for(int j=0; j<3; j++)
    System.out.print("*");  

  for(int j=0; j<3; j++)
    System.out.print("+");

  for(int j=0; j<3; j++)
    System.out.print("-"); 
}

Output:

***+++---

Answer 1

There can be many ways to do it. One of the ways is as follows:

public class Main {
    public static void main(String args[]) {
        char[] patternChars = { '*', '+', '-' };
        int repeat = 3;
        for (int i = 0; i < patternChars.length * 2; i++) {
            if (i < patternChars.length) {
                printChars(patternChars[i], repeat);
            } else {
                printChars(patternChars[patternChars.length * 2 - i - 1], repeat);
            }
        }
    }

    static void printChars(char ch, int repeat) {
        for (int i = 1; i <= repeat; i++) {
            System.out.print(ch);
        }
    }
}

Output:

***+++------+++***

The main feature of this solution is, if you add more characters to the char array, it will work without changing anything else eg the output for char[] patternChars = { '*', '+', '-','$' }; will be as follows:

***+++---$$$$$$---+++***

Answer 2

Your pattern consists of three distinct characters repeated three times in an ascending / descending order. I would simplify the problem, place each character into an array and iterate the array printing each element three times. Like,

char[] arr = { '*', '+', '-', '-', '+', '*' };
for (char ch : arr) {
    System.out.print(ch);
    System.out.print(ch);
    System.out.print(ch);
}
System.out.println();

Outputs (as requested)

***+++------+++***

Or, just iterate the characters in your desired output. Like,

String s = "***+++------+++***";
for (int i = 0; i < s.length(); i++) {
    System.out.print(s.charAt(i));
}
System.out.println();