This code is inside the main function:
Scanner input = new Scanner(System.in);
System.out.println(\"Type a sentence\");
String sentence = input
Per modifications to the original post, where the OP is now indicating that his goal is to reverse the letter order of the words within a sentence, but to leave the words in their initial positions.
The simplest way to do this, I think, is to make use of the String split function, iterate through the words, and reverse their orders.
String[] words = sentence.split(" "); // splits on the space between words
for (int i = 0; i < words.length; i++) {
String word = words[i];
System.out.print(reverseWord(word));
if (i < words.length-1) {
System.out.print(" "); // space after all words but the last
}
}
Where the method reverseWord is defined as:
public String reverseWord(String word) {
for( int i = 0; i < word.length(); i++) {
stk.push(word.charAt(i));
}
return stk.empty();
}
And where the empty method has been changed to:
public String empty() {
String stackWord = "";
while (this.first != null)
stackWord += this.pop();
return stackWord;
}
Original response
The original question indicated that the OP wanted to completely reverse the sentence.
You've got a double-looping construct where you don't really need it.
Consider this logic:
So:
for( int i = 0; i < sentence.length(); i++) {
stk.push(sentence.charAt(i));
}
stk.empty();