How can I perform multiplication without the ‘*’ operator?

by

Think about how you multiply in decimal using pencil and paper:

  12
x 26
----
  72
 24
----
 312

What does multiplication look like in binary?

   0111
x  0101
-------
   0111
  0000
 0111
-------
 100011

Notice anything? Unlike multiplication in decimal, where you need to memorize the “times table,” when multiplying in binary, you are always multiplying one of the terms by either 0 or 1 before writing it down in the list addends. There’s no times table needed. If the digit of the second term is 1, you add in the first term. If it’s 0, you don’t. Also note how the addends are progressively shifted over to the left.

If you’re unsure of this, do a few binary multiplications on paper. When you’re done, convert the result back to decimal and see if it’s correct. After you’ve done a few, I think you’ll get the idea how binary multiplication can be implemented using shifts and adds.

More Related Contents:

  1. Java equivalent to C++ arrow [closed]
  2. What's the c++ version of this java map code [closed]
  3. What is a shell script, makefile and ant file [closed]
  4. Run c/java/python with PHP? [duplicate]
  5. Can I see another sample of this program? I'm having difficulty in understanding it [closed]
  6. java vs C++ in pre and post increment
  7. Division In C++ and java?
  8. What is the difference between Java Garbage collection and C++ object destruction? [closed]
  9. How to create a Java ArrayList in C
  10. java.lang.ClassNotFoundException: Didn’t find class on path: dexpathlist
  11. Is there a way to simulate the C++ ‘friend’ concept in Java?
  12. How to call Java functions from C++?
  13. Missing return statement in a non-void method compiles
  14. Selenium WebDriver: Wait for complex page with JavaScript to load
  15. BitSet to and from integer/long
  16. Why are strings immutable in many programming languages? [duplicate]
  17. Tool to convert java to c# code [closed]
  18. Why hypot() function is so slow?
  19. How to compile dynamic library for a JNI application on linux?
  20. Technical reasons behind formatting when incrementing by 1 in a ‘for’ loop?
  21. How to call C++ from Java?
  22. What’s the C++ idiom equivalent to the Java static block?
  23. why is 1>>32 == 1?
  24. Generating Java interface with SWIG
  25. What is inlining?
  26. Algorithm – How to delete duplicate elements in a list efficiently?
  27. Java equivalent of C++ encryption [duplicate]
  28. Why is there no parameter contra-variance for overriding?
  29. Java Operators : |= bitwise OR and assign example [duplicate]
  30. Finding the median value of an array?

Leave a Comment