递归字符串超出界限

Question

void two(int i)
{
    if(i<s.length());
    {
        char a=s.charAt(i);
        if(a==' ')
            a-=2;               
        a+=2;
        if((a<64||a>90)&&a!=32)
            a-=26;
        System.out.print(a);
        two(i+1);
    }
}

s is a global variable. When I execute, it gives my output correctly, but at the end it gives me the following error:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 12

What is happening when the computer closes its workspaces in executing this recursive method?

Answer 1

Remove the semicolon after the if statement, as it represents just an empty statement that's being executed once per a method called. This makes the remaining statements within the brackets not bound to the if statement and they are executed every time the method is called.

Since you increase the index i on each recursive call and the statements in the brackets are executed independently from the if , then you get an ArrayIndexOutOfBoundsException on char a=s.charAt(i);

if(i<s.length());
                ↑

You should end up with something like:

if(i<s.length()) {
    char a=s.charAt(i);
    if(a==' ')
        a-=2;               
    a+=2;
    if((a<64||a>90)&&a!=32)
        a-=26;
    System.out.print(a);
    two(i+1);
}