Print a String 'X' Times (No Loop)

Question

Is it possible to print a string 'x' times?

For example if given the string

String q = "*";

Let's say the user entered the number '4' for the amount of times that they wanted the string repeated.

The program would print:

****

Answer 1

You can use recursion like this

private void printStar(int n){
    if(n > 0){
        System.out.print("*");
        printStar(n-1);
    }
}

And call the method like this initially - printStar(4);

Answer 2

You can make use of a char[] array of given length to build a String, then replace each character with *:

String repeatedStar = new String(new char[4]).replace('\0', '*');

Well, that would use a loop internally though.

Answer 3

From the Apache commons common-lang, use StringUtils.repeat:

System.out.println(StringUtils.repeat(q,4));

Answer 4

Although it probably loops internally, you could use Guava's Strings avoiding loops in the user code:

System.out.println(Strings.repeat("*", 4));

Answer 5

In recursion

printStar(int x)
{
   if(x > 0)
   {
     System.out.print("*");
     printStar(x-1);
   }
}

Answer 6

I know the point is probably to use recursion, but recursion in this case is a horrible solution. Here's a solution that is more efficient (though it very likely uses a loop in Arrays.fill!)

public static void printNX(int n)
{
    char[] c = new char[n];
    Arrays.fill(c, 'x');
    System.out.println(new String(c));
}

Of course, it's possible that Arrays.fill is calls into native code which is optimized to use an efficient instruction for filling the array and avoids a loop. But you never know.

I don't necessarily agree that using recursion "isn't looping"; all this is doing is thrashing the stack; the the CPU will still technically loop by continually jumping back to the top of the recursive function.