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CS255 Homework Assignment 5 - Array and Bit manipulations in C

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• Preparation

  • To do this project, you must obtain a copy of the prepared files with EGTAPI

    Use project code hw5

    You will have create a hw5 folder containing these program files:

    Makefile Makefile for homework 5 hw5.h Header file for hw5.c hw5.c C Project file for hw5 where you write 4 functions sol.o My compiled solution C program used to check your functions test1.c Test program for the sieveOfE() function test2.c Test program for the isPrime() function test3.c Test program for the lastPrime() function test4.c Test program for the printPrimes() function

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• Part 1 of the assignment
  • Part 1: (40 pts)

    Write the function void sieveOfE(unsigned in prime[], int N ) that find all prime numbers that are less than or equal to N using the Sieve of Erathothenes algorithm. The Sieve of Erathothenes algorithm is described on Wikipedia: click here It uses a boolean array prime[ ] where prime[k] = true if the number k is prime; otherwise prime[k] = false Instead of an array of boolean, you must use a bit array in this assignment: The parameter prime[ ] is a bit array (as discussed in class) The bit value 1 represents true (= prime) and the bit value 0 represents false (= not prime)

  • Warning:

    Do not initial the bit array with a loop where you set each bit with a setBit( ) operation: you will use too many iterations Because each array element in the bit array is a unsigned int which is 32 bits, you should use an assignment to initial all 32 bits at once: prime[k] = bit pattern with all bits 1 I'll let you figure out the syntax to write the bit pattern in C.

  • How to compile and test your sieveOfE() function:

    To compile the test1 program to test your sieveOfE( ) function, type this command: make test1 To run the test1 program to test your sieveOfE( ) function, type this command: test1

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• Part 2 of the assignment
  • Part 2: (20 pts)

    Write the function int isPrime(unsigned in prime[], int n ) that returns 1 (must be the value 1) if according to prime[] (which is the output of sieveOfE( )), the number n is prime and returns 0 otherwise.

  • How to compile and test your isPrime() function:

    To compile the test2 program to test your isPrime( ) function, type this command: make test2 To run the test2 program to test your isPrime( ) function, type this command: test2

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• Part 3 of the assignment
  • Part 3: (20 pts)

    Write the function int lastPrime(unsigned in prime[], int N ) that returns the largest prime number that is <= N according to the bit array prime[ ] (which is the output of sieveOfE( ))

  • How to compile and test your lastPrime() function:

    To compile the test3 program to test your lastPrime( ) function, type this command: make test3 To run the test3 program to test your lastPrime( ) function, type this command: test3

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• Part 4 of the assignment
  • Part 4: (20 pts)

    Write the function void printPrimes(unsigned in prime[], int k1, int k2, int N ) that prints the k1th to the k2th prime numbers but only for prime numbers <= N The number 2 is considered the first (i.e.: #1) prime number

  • How to compile and test your printPrimes() function:

    To compile the test4 program to test your printPrimes( ) function, type this command: make test4 To run the test4 program to test your printPrimes( ) function, type this command: test4

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• Debugging help
  • Crashes:

    A C program can crash without giving you any hint on which statement causes the crash If your C program crashes, you must use a debugger to locate the crash site (= the statement that causes the crash)

    I have discussed how to use the gdb debugger in class and you can find my gdb slides here: click here

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• Turn in

  Use EGTAPI to turn in your hw5.c program file with assignment code hw5

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• Extension request
  • Use EGTAPI to request an extension with the assignment code hw5

    You must make the extenion request before the deadline of the homework

    Your request will be successful if you have not exceeded the maximum number of "free" (no-questions-asked) requests allowed