CS 136 Assignment 3

Note: float and double and long are prohibited.

Due Wednesday, Oct. 3 at 11:59 am sharp. Late submissions will receive half marks if submitted before Dec. 3 at 11:59 AM sharp.

All work must be submitted to the Marmoset submission system. See the preamble of assignment 1 for more information.

For this assignment, you will submit C program files to Marmoset for grading. Future assignments will require that you submit C, Racket, written work, or some combination.

Your C submissions will be compiled on Ubuntu Linux using the LLVM compiler. They will be executed in the clang safe execution environment. Marmoset will award a nonzero grade when all of these conditions are met:

• the submission (when combined with correct testing components supplied by Marmoset) compiles without error;
• the submission runs without error, as reported by clang;
• the submission completes within the Marmoset time and memory limits (one or a few seconds of CPU; 128MB of RAM);
• the submission generates the correct output

You should develop and test your programs prior to submission using the gedit tool on Ubuntu Linux with the CS136 RunC plugin installed. Instructors and TAs will decline to provide assistance unless the program output and clang output are both available.

Hand Marking:

When writing your C code, you should follow the guidelines and principles within the C Style and Documentation Guide found HERE.

There is no hand marking on this assignment but style and documentation in your C code will be marked in later assignments.

Assignment 3 Problem 1a. 10 Marks, File: galaxy.compile.err

#include <stdio.h>
int main(void){
   int x;
   printf("The answer is %d\n",x);
   return 0;
}

Assignment 3 Problem 1b. 10 Marks, File: galaxy.c

Assignment 3 Problem 2a. 10 Marks, File: lcm.c

• gcdui.c

  // gcdui.h -- Main program and user interface for GCD
  
  #include <stdio.h>
  #include "gcd.h"
  
  int main(void){
     int x = 42;
     int y = 88;
     int gcdxy = gcd(x,y);
     printf("The gcd is %d\n",gcdxy);
     return 0;
  }
  

• gcd.h

  // Greatest Common Divisor by Euclid's Algorithm
  
  // Provides:  gcd(a,b) consumes non-negative ints
  //                     a and b and produces the greatest
  //                     d such that d divides a and
  //                     d divides b
  
  int gcd(int a, int b);
  

• gcd.c

  // Implementation of gcd.h
  
  #include "gcd.h"
  
  int gcd(int a, int b){
     if (b == 0) return a;
     return gcd(b, a%b);    // % is remainder on division
  }
  

Assignment 3 Problem 2b. 10 Marks, File: gcd.c

Assignment 3 Problem 3a. 5 Marks, File: playnewgame.c

   // file: newgame.h
   // Provides:  startgame, guess

   void startgame(int n);
   // starts a new game in which the
   //    game [this module] chooses a secret integer
   //    between 1 and n, and you [the client module]
   //    tries to guess it

   char guess(int x); 
   //     consumes an integer x and produces
   //     one of 'r' or 'h' or 'l', depending on 
   //     whether x is equal to, greater than, or less than
   //     the secret integer

   // Player for ordered guessing game
   // Provides:  playgame

   int playgame(int n);
   //              uses "newgame.h" to play an entire
   //              game of size n, and produces m,
   //              the total number of guesses actually
   //              used by playgame to produce 'r'

You may assume that n<2^31. You may not use long or long long.

Assignment 3 Problem 3b. 5 Marks, File: playnewgame.c