Problem

Remember that a while loop will execute infinitely until a specified condition is met. A for loop is similar except that the number of iterations is specified as an argument for the loop. Using both for and while loops, create a program that prints the powers of 2 from <math>2^0</math> <math>2^9</math>.

Your output should look something like this:

2 to the power of 0 is 1 2 to the power of 1 is 2 2 to the power of 2 is 4 2 to the power of 3 is 8 2 to the power of 4 is 16 2 to the power of 5 is 32 2 to the power of 6 is 64 2 to the power of 7 is 128 2 to the power of 8 is 256 2 to the power of 9 is 512

Do not use any of Java's Math class functions.

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Solution

You will need to declare 2 variables for this problem, one for the exponent and one for the answer.

    int exp;
    int ans;

You know that you need the powers of 2 from <math>2^0</math> <math>2^9</math>, your program will need to loop through 10 times. Since the number of iterations is known, you should use a for loop to calculate each exponent.

    for (int i=0; i<10; i++)
    {
      ans=1;
      exp=i;
			
      while(exp>0)
      {
        ans *= 2;
        exp --;
      }
			
      System.out.println("2 to the power of " + i + " is " + ans);
    }
  }	
}

Code

Solution Code

class PowersOfTwo
{
  public static void main (String[] args)
  {
    int exp;
    int ans;
		
    for (int i=0; i<10; i++)
    {
      ans=1;
      exp=i;
			
      while(exp>0)
      {
        ans *= 2;
        exp --;
      }
			
      System.out.println("2 to the power of " + i + " is " + ans);
    }
  }	
}