Question

Consider the following Java method:

static String mystery (int n){
StackOfIntegerInterface stack = new ArrayStackOfInteger();
while (n >=1){
stack.push(n % 2);
n = n/2;
}
String result = "";
while(!stack.isEmpty()){
result += stack.pop();
}
return result;
}
What is the value returned by the method call mystery (11)?
In 8 words or less, describe what this function does.

Answer 1

The Java method converts a decimal number to its binary representation. For the input of 11, it returns the string "1011". The process utilizes a stack to reverse the order of the binary digits.

Step-by-step explanation:

The Java method described in the question converts an integer (n) into its binary representation using a stack data structure. When we call mystery(11), the method performs the following steps:

1. It creates a stack where binary digits will be stored.
2. Then, it enters a loop where it repeatedly divides 11 by 2 and pushes the remainder onto the stack. This process is continued until the number becomes less than 1.
3. It enters another loop to pop elements from the stack and concatenate them into a string which forms the binary representation.

The expected returned value for mystery(11) is "1011", which is the binary equivalent of the decimal number 11.

In essence, this function converts decimal to binary.