Homework 10
Write a program that compares the real running times of the three sorting algorithms that we have discussed in class (Selection sort, Mergesort, and Quicksort), plus another N^2 algorithm of your choice: Insertion sort or Bubble sort.
Your program should read an arbitrary sequence of integers into an array from a file, sort the array using a particular sorting algorithm, and then print your results. Your executable will prompt the user for two arguments: the sort to use (i, s, b, m, or q) and the name of the input file. The input file will contain the number of integers on the first line, followed by one integer on each subsequent line. Sample files are available here:
Data Files Code
To time your sorting algorithms, use the function gettimeofday() (recall that we used this function early in the semester). Please note that your timings should not include printing the sorted array to the console since this will add a significant amount of time and skew the results, especially for small inputs. To check your algorithm, print the results outside your sort functions, after timing the sort.
The gettimeofday() function looks like this:
int gettimeofday(struct timeval *tv, struct timezone *tz);
The timeval structure has the following form:
struct timeval
{
long tv_sec; // seconds
long tv_usec; // microseconds
};
To time each sort, do something like this:
#include <sys/time.h>
...
timeval timeBefore, timeAfter;
long diffSeconds, diffUSeconds;
gettimeofday(&timeBefore, NULL);
InsertionSort(A);
gettimeofday(&timeAfter, NULL);
diffSeconds = timeAfter.tv_sec - timeBefore.tv_sec;
diffUSeconds = timeAfter.tv_usec - timeBefore.tv_usec;
cout << diffSeconds + diffUSeconds/1000000.0 << " seconds" << endl;
Record and plot your results (input size vs. running time) for various size inputs ranging from 100 integers to at least 500,000. Also, include a brief discussion of the results. Hand in a printed copy of your results and discussion in class, and email me a copy of your program.