Printing Specific Pattern using for Loop in Java

Question

i have to print specific pattern using Java for loop . Input will be 4 characters eg.

    a, b , c, d  

now what i have to print is

    aaaa
    aaab
    aaac
    aaad
    aaba
    abbb
    aabc

And so on.. i have tried some pyramids codes in java and understand to code nested for loops , but really getting no idea how to print this , Please guide me how i can achieve this . Thank You

Answer 1

Count from 0 to nⁿ-1, where n is the number of characters. For each count value, determine its base-n representation. Pad to the left with zeroes up to width n. Use each digit as an index into the characters. Print.

Answer 2

If you absolutely must use loops, you can nest some loops

for(char c1 = 'a'; c1<= 'd'; c1++)
{
    for(char c2 = 'a'; c2<= 'd'; c2++)
    {
        for(char c3 = 'a'; c3<= 'd'; c3++)
        {
            for(char c4 = 'a'; c4<= 'd'; c4++)
            {
                //print some combination of c1, c2, c3, and c4
            }
        }
    }
}

---

If your inputs aren't contiguous chars, than your loops might look like

char[] inputs
//initialize inputs
for(int i1 = 0; i1 < inputs.length; i++)
{
    char c1 = inputs[i1];
    ...
}