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#include <iostream>
#include <fstream>
#include <sstream>
#include <algorithm>
#include <ctime>
#include "Student.h"
using namespace std;
/*
* Read in a file containing student records and create an array of Student
* objects
*
* @param file The filename
* @param num The number of students in the file
* @return An array of Student objects
*/
Student* readStudentsFromFile(string filename, int num) {
ifstream studentsStream;
studentsStream.open(filename.c_str());
string line, name, school, sid;
int id;
static Student* readArray = new Student [num]; //An array of student object that will contain the read objects
if (!studentsStream.is_open()) {
cerr << "Couldn't open the file " << filename << endl;
return NULL;
}
while (!studentsStream.eof()) {
for(int i=0;i<num;i++) {
getline(studentsStream, line);
istringstream iss(line);
getline(iss, name, ',');
getline(iss, sid, ',');
getline(iss, school, ',');
istringstream idConv(sid);
idConv >> id;
readArray[i] = Student(id,name,school); //An array of Student objects
}//End of for loop
}//End of while
studentsStream.close();
return readArray;
}//End of readStudentsFromFile
/*
* Write an array of Student objects to a file
*
* @param students The array of Student objects to write out
* @param filename The output filename
*/
void writeStudentsToFile(Student students[], int num, string filename) {
ofstream output(filename.c_str());
output.open(filename);
for(int i=0;i<num;i++) {
string str=students[i].toString();
output << str<<"\n"<<endl;
}//End of for loop
output.close();
}//End of writeStudentsToFile
/*
* Find students belonging to both groups.
*
* This function checks each student in group1 for membership in group2 by
* comparing it with every student in group2.
*
* @param group1 A group of Students
* @param group2 A group of Students
* @param numCommon number of students belonging to both groups
* @return An array of Students which belong to both group1 and group2
*/
Student* findCommonStudents1(Student group1[], int len1, Student group2[],
int len2, int numCommon) {
Student *commonArray1 = new Student[numCommon];//An array that will hold the common students
int counter=0;
for(int i=0;i<len1;i++) {
for(int a=0;a<len2;a++) {
if(group1[i]==group2[a]) {
commonArray1[counter]=group1[i];
counter++;
}//enf of if statment
}//end of inner for loop
}//end of outer for loop
return commonArray1;
}//end of findCommonStudents1
/*
* Find students belonging to both groups.
*
* This function checks each student in group1 for membership in group2 by
* doing a binary search on group2.
*
* @param group1 A group of Students
* @param group2 A group of Students
* @param numCommon number of students belonging to both groups
* @return An array of Students which belong to both group1 and group2
*/
Student* findCommonStudents2(Student group1[], int len1, Student group2[],
int len2, int numCommon) {
int counter=0;
sort(group1, group1 + len1);
sort(group2, group2 + len2);
Student *commonArray2 = new Student[numCommon];
/*
* library function to binary search an array for the given value
* Note that values must be comparable with the < operator
*/
for(int i=0;i<len1;i++) {
bool found = binary_search(group2, group2 + len2, group1[i]);
if(found==true){
commonArray2[counter]=group1[i];
counter++;
}//End of if loop
}//End of for loop
return commonArray2;
}//End of findCommonStudents2
int main() {
/*
* DO NOT CHANGE ANY OF THE CODE BELOW
* Here just to help you with testing and timing your functions
*/
/***** These files provided to help you with initial testing *****/
const int UC_SIZE = 10;
const int SMC_SIZE = 5;
const int SMC_UC_GRADS_SIZE = 2;
Student* uc = readStudentsFromFile("sample_uc_students.txt", UC_SIZE);
Student* smc = readStudentsFromFile("sample_smc_grads.txt", SMC_SIZE);
/********************************** Use these files for the output you submit *************************/
//const int UC_SIZE = 350000;
//const int SMC_SIZE = 75000;
//const int SMC_UC_GRADS_SIZE = 25000;
//Student* uc = readStudentsFromFile("uc_students.txt", UC_SIZE);
//Student* smc = readStudentsFromFile("smc_grads.txt", SMC_SIZE);
// Rough timing
time_t start, end;
time(&start);
Student* common1 = findCommonStudents1(uc, UC_SIZE, smc, SMC_SIZE,
SMC_UC_GRADS_SIZE);
time(&end);
cout << "Using linear search it took " << difftime(end, start) << " seconds."
<< endl;
/*
* library sort function to sort an array: sort(arr, arr+size)
* Note that values must be comparable with the < operator
*/
sort(common1, common1 + SMC_UC_GRADS_SIZE);
writeStudentsToFile(common1, SMC_UC_GRADS_SIZE, "smc_grads_at_uc_1.txt");
time(&start);
Student* common2 = findCommonStudents2(uc, UC_SIZE, smc, SMC_SIZE,
SMC_UC_GRADS_SIZE);
time(&end);
cout << "Using binary search it took " << difftime(end, start)
<< " seconds." << endl;
sort(common2, common2 + SMC_UC_GRADS_SIZE);
writeStudentsToFile(common2, SMC_UC_GRADS_SIZE, "smc_grads_at_uc_2.txt");
delete[] smc;
delete[] uc;
delete[] common1;
delete[] common2;
return 0;
}
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