sorting.cpp

sorting input lines developed by C++ in linux environment

#include <iostream>
#include <fstream>
#include <string>
#include <cassert>
using namespace std;

#define MAX_NAME 32
#define SIZE 255

#define TRUE  1
#define FALSE 0

struct student {
	char lastName[MAX_NAME + 1];
	char firstName[MAX_NAME + 1];
	int studentNumber;
	int examResult; // (0 - 100)
};

template<class T>
int compare(T first, T second){
        if(first > second)
                return 1;
        else if(first < second)
                return  -1;
        else
                return 0;
}

template <class T>
void MergeSort(T a[], int capacity, int (*comapre)(T, T)) {
        int first = 0;
        int last = size - 1;
        if((*compare)() == -1){
                int mid = (first + last) / 2;
                MergeSort(a, mid, (*compare)(a[first], a[mid]));
                MergeSort(a, mid + 1, (*compare)(a[mid], a[last]));
                merge(a, first, mid, last);
       	}
}

template <class T>
void merge(T a[], int first, int mid, int last) {
	int ndx1 = first;
	int last1 = mid;
	int ndx2 = mid + 1;
	int last2 = last;
	int i = 0;
	int j;
	T* temp = new T[last - first + 1];
	if(!temp) {
		cerr << "Error allocating memory.\n";
		exit(1);
	}
	while(ndx1 <= last1 && ndx2 <= last2) {
		if(a[ndx1] <= a[ndx2])
			temp[i++] = a[ndx1++];
		else

			temp[i++] = a[ndx2++];
	}
	while(ndx1 <= last1)
		temp[i++] = a[mdx1++];
	while(ndx2 <= last2)
		temp[i++] = a[ndx2++];

	i = 0;
	for(j = first; j <= last; j++)
		a[j] = temp[i++];
		delete [] temp;
}

template <class T>
void BubbleSort(T a[], int capacity, int(*compare)(T,T))
{
	int sorted = FALSE;
  	while (sorted == FALSE)
  	{
    		sorted = TRUE;
    		for (int i = 0; i < last; i++)
    		{
      			if (a[i] > a[i+1])
      			{
        			swap (a[i], a[i+1]);
        			sorted = FALSE;
      			}
    		}
  	}
}

template <class T>                                                                                             void swap (char &a, char &b) {
	T temp = a;
  	a = b;
  	b = temp;
}

int main() {
	ifstream inputFile;
	ofstream outputFile;
	string inputFileName;
	string outputFileName;
	char orderChoice;
	char algorithmChoice;
	cout << "Enter input file: " << inputFileName << endl;
	cout << "Enter output file: " << outputFileName << endl;
	inputFile.open(inputFileName.data());
	assert(inputFile.is_open());
	outputFile.open(outputFileName.data());
	assert(outputFile.is_open());
	student a[SIZE];
	int capacity;
	inputFile >> capacity;
        for(int i = 0; i < capacity; i++){
                if(inputFile.eof()) break;
                inputFile >> a[i].lastName >> a[i].firstName >> a[i].studentNumber >> a[i].examResult;
 	} 

	cout << "n: by last name " << endl;
	cout << "s: by student number " << endl;
	cout << "r: by exam result " << endl;
	
        while((orderChoice != 'n') || (orderChoice != 's') || (orderChoice != 'r')){
		cout << "Enter option [nsr]: " << orderChoice << endl;
		cin >> orderChoice;
	}

	cout << "Enter the sorting algorithm to use: " << endl;
	cout << "b: bubble sort " << endl;
	cout << "m: merge sort " << endl;
        
	while((algorithmChoice != 'b') || (algorithmChoice != 'm')){
		cout << "Enter option [bm]: " << algorithmChoice << endl;
                cin >> algorithmChoice;
        }
        if(algorithmChoice == 'b'){
                if(orderChoice == 'n')
                        BubbleSort(a, capacity, compare(a[0].lastName, a[capacity - 1].lastName));
                else if(orderChoice == 's')
                        BubbleSort(a, capacity, compare(a[0].studentNumber, a[capacity - 1].studentNumber));
                else if(orderChoice == 'r')
                        BubbleSort(a, capacity, compare(a[0].examResult, a[capacity - 1].examResult));
        }
                                                                                                               
        else if(algorithmChoice == 'm'){
		if(orderChoice == 'n')
                        MergeSort(a, capacity, compare(a[0].lastName, a[capacity - 1].lastName));
                else if(orderChoice == 's')
                        MergeSort(a, capacity, compare(a[0].studentNumber, a[capacity - 1].studentNumber));
                else if(orderChoice == 'r')
                        MergeSort(a, capacity, compare(a[0].examResult, a[capacity - 1].examResult));
        }
	
        for(int i = capacity-1; i >= 0; i--){
                outputFile << a[i].lastName << a[i].firstName << a[i].studentNumber << a[i].examResult << endl;
        }

	inputFile.close();
	outputFile.close();
	cout << "Finished!!!" << endl;
}