title: Program calculating power of 2
body: <p>I'm writing a simple program to calculate power of 2. A user would enter the number of times they want to calculate the power of 2, let say the user enter 4, my program would returns 2,4,8,16.Here is the code</p>
  
  <pre><code>import java.util.Scanner;
  
  public class PowersOf2
  
  {
  
  public static void main(String[] args)
  
  {
  
  int numPowersOf2;        
  //How many powers of 2 to compute
  
  int nextPowerOf2 = 1;    
  //Current power of  2
  
  int exponent = 0;            
  
  //Exponent for current power of 2 -- this
  
  //also serves as a counter for the loop
  
  Scanner scan = new Scanner(System.in);
  
          System.out.println("How many powers of 2 would you like printed?");
          numPowersOf2 = scan.nextInt();
  
          //print a message saying how many powers of 2 will be printed
          //initialize exponent -- the first thing printed is 2 to the what?
  
      System.out.println("Here are the first " + numPowersOf2 + " power of 2");
  
  
        while (exponent&lt;numPowersOf2)
          {
            //print out current power of 2
  
              nextPowerOf2=nextPowerOf2*2;
  
              exponent++;
  
              System.out.println(nextPowerOf2);
              //find next power of 2 -- how do you get this from the last one?
  
              //increment exponent
               }
          }
  }
  </code></pre>
  
  <p>If I want it to start at 0 first say like 2^0=1, so if user enter 4, it would give back 1,2,4,8 instead of 2,4,8,16. How do I modify this to get that?</p>