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Errors out of bounds saying,

java.lang.StringIndexOutOfBoundsException: String index out of range: 6 (in.java.lang.String)

when I run the code. I am trying to find how many identical characters two strings have in the same spots.

Public static void main(String[] args) {
    System.out.println(countAlike("happy","damp");
}

public static int countAlike(String a, String b) {
    int acount = a.length();
    int bcount = b.length();
    int countAlike = 0;
    for(int i = 0; i <= bcount; i++){
        for(int l = 0; l <= bcount; i++){
            if(a.substring(i,i+1).equals(b.substring(l,l+1))){
                countAlike += 1;
            }
            else{ 
            }
        }
    }
    return countAlike;
}
  • `String` index's start at 0, so `for(int i = 0; i <= bcount; i++)` will go out of bounds on the last iteration. Change it to `i < bcount` – GBlodgett Oct 01 '18 at 19:34
  • i <= bcount should be i < acount as well as l <= bcount shoul be l < bcount – emecas Oct 01 '18 at 19:36
  • What should this program actually do? Return the amount of equal characters from `a` and `b`, keeping position in mind? – Glains Oct 01 '18 at 19:39
  • Yup, forgot to state that! Screw up on my part. –  Oct 01 '18 at 20:13

3 Answers3

1

3 issues here:

1) Change <= bcount to < bcount.

2) In your 2nd for loop , you are doing i++ but it should be l++

3) The condition in you first for loop should be i < acount, not i<bcount

nupadhyaya
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1

Indexes for String characters in Java like in most languages start with 0, therefore, the last index of the strings actually is str.length() - 1.

When you test with <=, your variable is incremented until the value is equal to your length, which is an out of bound index.

Rather test with < for both of your tests. Your variable will stop after the last character of that string instead of trying one last time with an index that does not exist.

Sirmyself
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When you run this code it will return 3, not sure if that is what you expected for the return value. You have to change a few things

  1. First for loop for(int i = 0; i < acount; i++)

  2. Second for loop for(int l = 0; i < bcount; l++)

    public static void main(String[] args){

    System.out.println(countAlike("happy","damp"));
}

public static int countAlike(String a, String b){

    int acount = a.length();
    int bcount = b.length();
    int countAlike = 0;
    for(int i = 0; i < acount; i++){
        for(int l = 0; l < bcount; l++){
            if(a.substring(i,i+1).equals(b.substring(l,l+1))){
                countAlike += 1;
                }
            else{}
        }
    }
    return countAlike;
}

If you have a System.out.println(a.substring(i, i+1)); and System.out.println(b.substring(l, l+1)); in your If statement in the for loop if will print out a a p p p p.

Jaybro90
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