Difference between revisions of "CSC231 Homework 3"

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=Assignment #3=
 
=Assignment #3=
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This assignment is due on Wednesday Oct. 1st, at 11:59 p.m. plus one minute.
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==Problem #1==
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Same problem as we did in class.  Below is the mystery program.  Its output is listed in the header of the program.
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<code><pre>
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/* mystery.cpp
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// D. T.
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// mystery program
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// To compile and run this program:
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//
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//    g++ mystery.cpp
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//    a.out
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//
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// The output of the program is the following
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//
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// 27001
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// -31534
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//
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// With what positive values were x and y initialized
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// at the beginning of the program.  Explain why.
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// (a short int contains 16 bits)
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*/
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#include <stdio.h>
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main() {
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    short int x = ?????;
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    short int y = ?????;
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    x = x+y;
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    printf( "%d\n", x );
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    x = x+y;
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    printf( "%d\n", x );
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}
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</pre></code>
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What two positive numbers are stored in x and y to create the output listed in the header?
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Explain your answer.
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==Problem #2==
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Assume that we want to compute the [http://en.wikipedia.org/wiki/Fibonacci_number Fibonacci] series with a compiled program. 
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*  How many terms can we correctly display if we use unsigned chars (8 bits) to store the Fibonacci terms?
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* How many terms if we use unsigned short ints (16 bits)?
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* How many terms if we use usigned ints (32 bits)?
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* How many terms if we use long unsigned ints of 64 bits?
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Explain carefully how you derive your answers.  Prefered answers are answers that contain a program (in the language of your choice) demonstrating/illustrating in one way or another the answers to the various questions.
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==Problem #3==
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Assume that we write a C or C++  program that displays all the powers of 2 in this fashion:
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<code><pre>
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unsigned int x = 1;
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while ( x ) {
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  printf ( "%d\n", x );
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  x = x * 2;
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}
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</pre></code>
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* Is the loop infinite?  Why?
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* If it is not infinite, how many times does it go through, and how many terms does it print?  Why?  What is the last number displayed?
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Store the answers to all 3 problems in a file called '''hw3.txt''' and submit it as follows:
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  submit hw3 hw3.txt

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Back to CSC231 Main Page

Assignment #3

This assignment is due on Wednesday Oct. 1st, at 11:59 p.m. plus one minute.

Problem #1

Same problem as we did in class. Below is the mystery program. Its output is listed in the header of the program. 


/* mystery.cpp
// D. T.
// mystery program
// To compile and run this program:
//
//     g++ mystery.cpp
//     a.out
//
// The output of the program is the following
//
// 27001
// -31534
//
// With what positive values were x and y initialized
// at the beginning of the program.  Explain why.
// (a short int contains 16 bits)
*/

#include <stdio.h>

main() {

    short int x = ?????;
    short int y = ?????;


    x = x+y;
    printf( "%d\n", x );

    x = x+y;
    printf( "%d\n", x );
}

What two positive numbers are stored in x and y to create the output listed in the header?

Explain your answer.

Problem #2

Assume that we want to compute the Fibonacci series with a compiled program.

  • How many terms can we correctly display if we use unsigned chars (8 bits) to store the Fibonacci terms?
  • How many terms if we use unsigned short ints (16 bits)?
  • How many terms if we use usigned ints (32 bits)?
  • How many terms if we use long unsigned ints of 64 bits?

Explain carefully how you derive your answers. Prefered answers are answers that contain a program (in the language of your choice) demonstrating/illustrating in one way or another the answers to the various questions.

Problem #3

Assume that we write a C or C++ program that displays all the powers of 2 in this fashion: 


unsigned int x = 1;

while ( x ) {
   printf ( "%d\n", x );
   x = x * 2;
}
  • Is the loop infinite? Why?
  • If it is not infinite, how many times does it go through, and how many terms does it print? Why? What is the last number displayed?


Store the answers to all 3 problems in a file called hw3.txt and submit it as follows: 

  submit hw3 hw3.txt
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