Answer:
//Begin class definition
public class DoubleCharTest{
//Begin the main method
public static void main(String [ ] args){
//Call the doubleChar method and pass some argument
System.out.println(doubleChar("There"));
}
//Method doubleChar
//Receives the original string as parameter
//Returns a new string where for every character in
//the original string, there are two characters
public static String doubleChar(String str){
//Initialize the new string to empty string
String newString = "";
//loop through each character in the original string
for(int i=0; i<str.length(); i++){
//At each cycle, get the character at that cycle
//and concatenate it with the new string twice
newString += str.charAt(i) + "" + str.charAt(i);
}
//End the for loop
//Return the new string
return newString;
} //End of the method
} // End of class declaration
Sample Output:
TThheerree
Step-by-step explanation:
The code above has been written in Java and it contains comments explaining each line of the code. Kindly go through the comments. The actual lines of executable codes have been written in bold-face to differentiate them from comments.
A sample output has also been given.
Snapshots of the program and sample output have also been attached.