Merge two strings letter by letter in Java?

Question

Given two strings, A and B, create a bigger string made of the first char of A, the first char of B, the second char of A, the second char of B, and so on. Any le

Answer 1

You've got a workable approach, but you could significantly simplify it by using a single loop with two counters:

int apos = 0, bpos = 0;
while (apos != a.length() || bpos != b.length()) {
    if (apos < a.length()) m += a.charAt(apos++);
    if (bpos < b.length()) m += b.charAt(bpos++);
}

In this loop you will "make progress" on each step by advancing apos, bpos, or both. Once a string runs out of characters, its corresponding pos stops advancing. The loop is over when both pos reach their ends.

Note: When you need to append to a string in a loop, use StringBuilder.