Cannot push 0 to stack in java

December 24, 2022

I am newbie in Java. I have the problem. This is my code

Stack<String> st = new Stack<String>();
int num=9;
while(num > 0){
    st.push(Integer.toString(num%2));
    num/=2;
}
int d=0;
if(!st.isEmpty()){
    d++;
    st.pop();
 }
System.out.println(d);

the result is 1.
But correct is 4.
I don’t know how to fix it. Sorry if my English is not good. Thankyou

>Solution :

Your problem is from line 8! When you define if, however you have to write while loop, NOT if statement

Another point is that your stack should be integer and its not essential to define stack with string

So try it:

Stack<Integer> st = new Stack<>();
int num = 9, d = 0;
while(num > 0){
    st.push(num%2);
    num /= 2;
}

while(!st.isEmpty()){
    d++;
    st.pop();
 }
System.out.println(d);