Question

import cs1.Keyboard;

public class charAT {
    public static void main(String[] args) {
        String s;

        //The telephone number should be 79575757
        System.out.println("Enter your telephone number");
        s = Keyboard.readString();

        int index1 = s.charAt(0);

This part does not work:

        if((char)index1 == 7){
            System.out.println("The second number is "+(char)index1);
        }
        else {
            System.out.println("This number is invalid");
        }
    }
}

What am I doing wrong?

Answer 1

First, charAt() method returns char, so your code should be like this:

char ch = s.charAt(0);

I changed the variable name from index1 to ch. charAt() method returns the char at the specified position, not an index.

Second, you should compare the char:

if (ch == '7') {

And the last, you can concatenate String and char like this:

System.out.println("The second number is "+ ch);