java, absolute beginner, error

[Marek707]

The program is to change a capital letter into a lowercase letter, and this is what it does pretty well. However, why is the phrase "Enter a letter" repeated twice at the second attempt and all following attempts? How can I correct it?

package com.mycompany.mavenproject2;

public class test1 { public static void main (String args[])throws java.io.IOException {

    char ch;       
    for(;;){
        System.out.println("Enter a letter");
        ch = (char) System.in.read();

         if(ch > 64 & ch < 91){
            ch += 32;
            System.out.println(ch);                               
        }
    }
}           

}

[jwyatt1999]

To debug this, I removed the (char) cast from ch and added System.out.println("Input: " + ch); after the ch = System.in.read(); line to see exactly what was being input after entering a capital letter then pressing Enter. Unsurprisingly, the capital letter is input and so is an ASCII carriage return (which has value 13), which causes the loop to repeat "Enter a letter" twice from the second attempt onwards.

This can be fixed by shuffling around where you call System.out.println("Enter a letter");.

The following code works on my system:

char ch;
System.out.println("Enter a letter");       
for(;;) {
    ch = (char) System.in.read();
    if (ch > 64 && ch < 91) {
        ch += 32;
        System.out.println(ch); 
        System.out.println("Enter a letter");                            
    }
}

Let me know if you have any questions :)

[Marek707]

It works fine. Thank you for your explanation!