CS 61C, Spring 2010
Due Friday, January 29, 2010 @ 11:59pm
This assignment checks your understanding of the material in P&H Chapter 1 as well as some number representation basics. It will also give you practice compiling and executing C programs.
Submit your solution by creating a directory named hw1 that contains files named cod.txt and bitcount.c. (Note that capitalization matters in file names; the submission program will not accept your submission if your file names differ at all from those specified.) From within that directory, type "submit hw1". Partners are not allowed on this assignment.
$ mkdir ~/hw $ cp -r ~cs61c/hw/01/ ~/hwAll the files referred in this homework will be in the folder you copied.
bitCount()
in bitcount.c
that returns the number of 1-bits in the binary representation of its unsigned integer argument. Remember to fill in the identification information and run the completed program to verify correctness.
/* Name: Lab section time: */ #include <stdio.h> int bitCount (unsigned int n); int main ( ) { printf ("# 1-bits in base 2 representation of %u = %d, should be 0\n", 0, bitCount (0)); printf ("# 1-bits in base 2 representation of %u = %d, should be 1\n", 1, bitCount (1)); printf ("# 1-bits in base 2 representation of %u = %d, should be 16\n", 2863311530u, bitCount (2863311530u)); printf ("# 1-bits in base 2 representation of %u = %d, should be 1\n", 536870912, bitCount (536870912)); printf ("# 1-bits in base 2 representation of %u = %d, should be 32\n", 4294967295u, bitCount (4294967295u)); return 0; } int bitCount (unsigned int n) { /* your code here */ }
# ./bitcount 17 2 # ./bitcount 255 8 # ./bitcount 10 20 too many arguments! # ./bitcount [the same result as from problem 5]You may assume that the single argument will always be an integer in the range from 0 to 2^31-1. You will find the function
atoi
helpful.
Extra for experts: Implement this exercise without using the library function atoi
(or something comparable).