lexical analyzer does not detect the correct string

Question

The lexical analyzer must accept a string with the same number of a and b.

The program accepts any chain that has a and b.

public static int i;

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
 Scanner input = new Scanner(System.in);
    String s;


    System.out.println("Input something to lexically analyze:  ");
    s = input.next( );
    int j = 0;

     if(s.charAt(i)=='a'||'b'){
      for (int i = 1; i < s.length(); i++) {  

            j++;

            if(i==j){
            System.out.println("cadena correcta");
            }
        }

     }
     else {
        System.out.println("cadena incorrecta\n");
        System.exit(0);
    }
 }

}

I am trying to count how many times a and b is repeated to know if you have the same number of letters but it has not worked for me.

It will be hard to help with the logic when the program doesn't even compile. You have multiple errors for `if(s.charAt(i)=='a'||'b'){`, at that point `i` isn't defined, did you mean `j`? Also, you can not compare against two characters like that, you need to do `if(s.charAt(j)=='a'||s.charAt(j)=='b'){` — Roger Lindsjö, Aug 09 '19 at 05:06

score 0 · Answer 1 · answered Aug 09 '19 at 04:50

The following code counts the number of as and bs in a string. It should guide you in the right direction.

String str = "aaabbabb";
int aCount = str.length() - str.replace("a", "").length();
int bCount = str.length() - str.replace("b", "").length();
System.out.println(aCount == bCount); // true

lexical analyzer does not detect the correct string

1 Answers1