NickName:raduns Ask DateTime:2013-08-21T01:21:47

Java Exception in Counting number of occurrences of character in a string

I am a java beginner and want to do some logic stuffs. I have started with a simple program (i.e) to find the total number of occurrences of a character in a string. But i ended up with this exception

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 52
    at java.lang.String.charAt(Unknown Source)

And i used the following code

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String myStr = "sofdaasdasdaofsdwerwtytuoftyutyusdfsdfsdcsadaswdeasd";
        // Counting number of occurences of 'of' in myStr
        int counter = 0;
        int totalLength = myStr.length();
        char char1;
        char char2;
        // To find of
        String myVal = "of";
        String cmpVal1;
        String cmpVal2;
        String cmpValStr;
        for (int i = 0; i < totalLength; i++) {
            char1 = myStr.charAt(i);
            cmpVal1 = Character.toString(char1);
            char2 = myStr.charAt(i + 1);
            cmpVal2 = Character.toString(char2);
            cmpValStr = cmpVal1 + cmpVal2;
            if (cmpValStr == myVal) {
                counter++;
            }

        }
        System.out.print(counter);
    }

}

Copyright Notice：Content Author:「raduns」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/18341252/java-exception-in-counting-number-of-occurrences-of-character-in-a-string

Answers

Luke Bigwood 2013-08-20T17:29:49

for (int i = 0; i < totalLength-1; i++) {\n //additional code..\n if (cmpValStr.equals(myVal)) {\n counter++;\n }\n}\n\n\nYour 'for' loop should look like that. Make sure you subtract 1 from the String's length due to your increment of char2.\n\nAlso, when comparing the two strings use the .equals()\n\nAlthough, if you're interested, this is how I would have done it:\n\nString myStr = \"sofdaasdasdaofsdwerwtytuoftyutyusdfsdfsdcsadaswdeasd\";\nint counter=0;\nfor(int i=0;i<myStr.length()-1;i++){\n if(myStr.subSequence(i, i+2).toString().contains(\"of\"))\n {\n counter++;\n }\n}\nSystem.out.print(counter);\n",

Daren 2013-08-20T17:25:10

this is your problem:\n\nchar2 = myStr.charAt(i + 1);\n\n\nyou go out of bounds with this on the last char.\n\ntry doing:\n\nfor (int i = 0; i < totalLength-1; i++)",