Power

This is a discussion on Power within the C++ Programming forums, part of the General Programming Boards category; I have this code to find the power of x^y. i already found out how to do x^y but am ...

  1. #1
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    Power

    I have this code to find the power of x^y. i already found out how to do x^y but am having trouble doing x^-y (x to the -y power) Here is my code
    Code:
    #include <iostream.h>
    int main()
    {
       double x,y;
       double sum = 1;
    
      cout << "Enter the X number : ";
      cin >> x;
      cout << "Enter the Y number : ";
      cin  >> y;
    
      for (int a =1; a<=y; a++)
      {
          sum = sum * x;
      }
    cout << sum << endl;
    
    cin >> hold;
    }
    Can anyone please give me hints to do x to the -y power?
    Thanks.

  2. #2
    Programming Sex-God Polymorphic OOP's Avatar
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    rather than multiplying sum by x multiply sum by the inverse of x

  3. #3
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    how do i do the inverse of x?

  4. #4
    ˇAmo fútbol!
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    1/x

  5. #5
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    yeah i know its 1/x but how do i do on c++?

  6. #6
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    Please help me? How do i do this program?

  7. #7
    Shadow12345
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    Unless this assignment specifically needs you to perform your own power calculations simply include math.h to your project and use pow(x, y) where it calculates the value of 'x' raised to the 'y' power.

    The inverse of a number is the number you can multiply by in order to get 1.

    x * (x/x^2) = 1;

    EDIT:
    1/x is the easier and better way to find the inverse
    Last edited by Shadow12345; 12-20-2002 at 02:35 PM.

  8. #8
    Programming Sex-God Polymorphic OOP's Avatar
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    Originally posted by sonict
    yeah i know its 1/x but how do i do on c++?
    Why do you think it would be any different?

    1.0 / x

  9. #9
    Veni Vidi Vice
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    I have this code to find the power of x^y. i already found out how to do x^y but am having trouble doing x^-y (x to the -y power)
    Simply do a check if y is greater or less than 0 and use the right method (the one you created or the 1/X method). And if you add a check for y == 0 (easy, returns 1), you will have a complete power function for integral values.

  10. #10
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    >Can anyone please give me hints to do x to the -y power?

    Realize that

    x^(-y) = 1 / (x^y)

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