This is an assignment that we use strings in Java to analyze a phone number. The error I am having is anything below tester=invalidCharacters(c); does not compile because every line past tester=invalidCharacters(c); is looking for a symbol or the class. In get invalidResults, all I am trying to do is evaluate a given string for non-alphabetical characters such as *,(,^,&,%,@,#,), and so on.

What to answer: Why is it producing an error, what will work, and is there an easier method WITHOUT using regex.

Here is the link to the assignment: http://cis.csuohio.edu/~hwang/teaching/cis260/assignments/assignment9.html

public class PhoneNumber {
            private int areacode;
            private int number;
            private int ext;

            /////Constructors/////
            //Third Constructor (given one string arg) "xxx-xxxxxxx" where first three are numbers and the remaining (7) are numbers or letters
            public PhoneNumber(String newNumber){
                    //Note: Set default ext to 0
                    ext=0;

                    ////Declare Temporary Storage and other variables////
                    //for the first three numbers
                    String areaCodeString;
                    //for the remaining seven characters
                    String newNumberString;
                    //For use in testing the second half of the string
                    boolean containsLetters;
                    boolean containsInvalid;

                    /////Separate the two parts of string/////
                    //Get the area code part of the string
                    areaCodeString=newNumber.substring(0,2);
                    //Convert the string and set it to the area code
                    areacode=Integer.parseInt(areaCodeString);

                    //Skip the "-" and Get the remaining part of the string
                    newNumberString=newNumber.substring(4);

                    //Create an array of characters from newNumberString to reuse in later methods for
                    int length=newNumberString.length();
                    char [] myCharacters= new char [length];
                    int i;
                    for (i=0;i<length;i++){
                        myCharacters [i]=newNumberString.charAt(i);
                    }

                    //Test if newNumberString contains letters & converting them into numbers
                    String reNewNumber="";
                    //Test for invalid characters
                    containsInvalid=getInvalidResults(newNumberString,length);
                    if (containsInvalid==false){
                        containsLetters=getCharResults(newNumberString,length);
                        if (containsLetters==true){
                            for (i=0;i<length;i++){
                            myCharacters [i]=(char)convertLetNum((myCharacters [i]));
                            reNewNumber=reNewNumber+myCharacters[i];
                            }
                        }
                    }
                    if (containsInvalid==false){
                    number=Integer.parseInt(reNewNumber);
                    }
                    else{
                        System.out.println("Error!"+"\t"+newNumber+" contains illegal characters. This number will be ignored and skipped.");
                    }
            }

            //////Primary Methods/Behaviors///////
            //Compare this phone number with the one passed by the caller
            public boolean equals(PhoneNumber pn){
                boolean equal;
                String concat=(areacode+"-"+number);
                String pN=pn.toString();
                if (concat==pN){
                    equal=true;
                }
                else{
                    equal=false;
                }
                return equal;
            }
            //Convert the stored number to a certain string depending on extension
            public String toString(){
                String returned;
                if(ext==0){
                    returned=(areacode+"-"+number);
                }
                else{
                    returned=(areacode+"-"+number+" ext "+ext);
                }
                return returned;
            }

            //////Secondary Methods///////
            //Method for testing if the second part of the string contains any letters
            public static boolean getCharResults(String newNumString,int getLength){
                //Recreate a character array
                int i;
                char [] myCharacters= new char [getLength];
                for (i=0;i<getLength;i++){
                    myCharacters [i]=newNumString.charAt(i);
                }
                boolean doesContainLetter=false;
                int j;
                for (j=0;j<getLength;j++){
                if ((Character.isDigit(myCharacters[j])==true)){
                    doesContainLetter=false;
                }
                else{
                    doesContainLetter=true;
                    return doesContainLetter;
                }
                }
                return doesContainLetter;
            }
            //Method for testing if the second part of the string contains any letters
            public static boolean getInvalidResults(String newNumString,int getLength){
                boolean doesContainInvalid=false;
                int i;
                char c;
                boolean tester;
                char [] invalidCharacters= new char [getLength];
                for (i=0;i<getLength;i++){
                    invalidCharacters [i]=newNumString.charAt(i);
                    c=invalidCharacters [i];
                    tester=invalidCharacters(c);
                    if(tester==true)){
                        doesContainInvalid=false;
                    }
                    else{
                        doesContainInvalid=true;
                        return doesContainInvalid;
                    }
                }
                    return doesContainInvalid;
            }

            //Method for evaluating string for invalid characters
            public boolean invalidCharacters(char letter){
                boolean returnNum=false;
                    switch (letter){
                        case 'A': return returnNum;
                        case 'B': return returnNum;
                        case 'C': return returnNum;
                        case 'D': return returnNum;
                        case 'E': return returnNum;
                        case 'F': return returnNum;
                        case 'G': return returnNum;
                        case 'H': return returnNum;
                        case 'I': return returnNum;
                        case 'J': return returnNum;
                        case 'K': return returnNum;
                        case 'L': return returnNum;
                        case 'M': return returnNum;
                        case 'N': return returnNum;
                        case 'O': return returnNum;
                        case 'P': return returnNum;
                        case 'Q': return returnNum;
                        case 'R': return returnNum;
                        case 'S': return returnNum;
                        case 'T': return returnNum;
                        case 'U': return returnNum;
                        case 'V': return returnNum;
                        case 'W': return returnNum;
                        case 'X': return returnNum;
                        case 'Y': return returnNum;
                        case 'Z': return returnNum;
                        default: return true;
                    }

            }
            //Method for converting letters to numbers
            public int convertLetNum(char letter){
                int returnNum;
                    switch (letter){
                        case 'A': returnNum=2;return returnNum;
                        case 'B': returnNum=2;return returnNum;
                        case 'C': returnNum=2;return returnNum;
                        case 'D': returnNum=3;return returnNum;
                        case 'E': returnNum=3;return returnNum;
                        case 'F': returnNum=3;return returnNum;
                        case 'G': returnNum=4;return returnNum;
                        case 'H': returnNum=4;return returnNum;
                        case 'I': returnNum=4;return returnNum;
                        case 'J': returnNum=5;return returnNum;
                        case 'K': returnNum=5;return returnNum;
                        case 'L': returnNum=5;return returnNum;
                        case 'M': returnNum=6;return returnNum;
                        case 'N': returnNum=6;return returnNum;
                        case 'O': returnNum=6;return returnNum;
                        case 'P': returnNum=7;return returnNum;
                        case 'Q': returnNum=7;return returnNum;
                        case 'R': returnNum=7;return returnNum;
                        case 'S': returnNum=7;return returnNum;
                        case 'T': returnNum=8;return returnNum;
                        case 'U': returnNum=8;return returnNum;
                        case 'V': returnNum=8;return returnNum;
                        case 'W': returnNum=9;return returnNum;
                        case 'X': returnNum=9;return returnNum;
                        case 'Y': returnNum=9;return returnNum;
                        case 'Z': returnNum=9;return returnNum;
                        default: return 0;
                    }

        }
    }

Note: Please Do not use this program to cheat in your own class. To ensure of this, I will take this question down if it has not been answered by the end of 2013, if I no longer need an explanation for it, or if the term for the class has ended.