C++ code modification help required ?

Question

Hi there

I am having lots of trouble with this program , I am really falling behind.
 Hopefully you can help me .


This program opens a text file, then it reads first name, last name, and test score. then it assigns scores and displays students by name, score, test score range, and highest score.

SAMPLE TEXT FILE : SACHIN TENDULKAR 100 SUNIL GAVASKAR 95 
these are first name last name test score order .. 


My progress till now .. 
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#include<iostream>
#include<fstream>
#include<string>


using namespace std;


struct StudentType
{string studentName;
int testScore;//Between 0 and 100
char grade;




};


void PrintNameHeader(ostream& out);
bool OpenInputFile(ifstream& inFile, string& infilename ); //OPEN input file
void Pause();// Pause
void ReadStudentData(ifstream& infile, StudentType student[], int& );// Read student infp including first and last name and test score
void AssignGrades(StudentType student[], int);//assign grades to each student
int HighestScore(const StudentType student[], int );//Get the highest scores
void PrintNamesWithHighestScore(const StudentType student[], int);//Print name/s with highest Scores
void DisplayAllStudents(const StudentType student[], int);//Display all students
void GetLowHighRangeValues(int& , int&);//for example a student types 50 100 , it will get all students within that range
void DisplayStudentsInRange(const StudentType student[], int, int, int);// display students in that range
void SortStudentsByName(StudentType student[], int);// sort students by name
void SortStudentsByScore(StudentType student[], int);// sort students by test score highest to lowest


const int NUM_STUDENTS = 20;






int main()
{


ifstream infile;
string inFilename;






StudentType student[NUM_STUDENTS];


int numStudents = 0;


PrintNameHeader(cout);


OpenInputFile(infile,inFilename);


ReadStudentData(infile, student, numStudents);




return 0;
}


//Function definitions


void PrintNameHeader(ostream& out)//Completed
{
cout <<"My name << endl;


}
bool OpenInputFile(ifstream& inFile, string& infilename) //COMPLETED
{






cout << "Enter the name of the .txt file that you want to open for input.\n";
cout << "Do not put spaces in the file name ";
cin >> infilename;
cout << endl;




inFile.open(infilename.c_str());
if (inFile.fail())
{
cout << "Sorry, the input file " << infilename <<" was not found"<< endl;\
return false;
}


cout << "Input file " << infilename << " is open for reading.\n\n";
return true;
}


void Pause()
{
cout << endl;


cin.ignore(80, '\n');


cout<<"Please hit the enter key to continue...\n";


cin.get();


}


void ReadStudentData(ifstream& infile, StudentType student[], int& numstudents)
{
string firstName,
LastName,
testScore;


int count = 0;


StudentType fullname;






if( infile)


for (int count; count < NUM_STUDENTS; count++)
{
cin >> firstName[count] >> LastName[count] >> testScore[count];


fullname[count]= firstName + ", " + LastName;


}








numstudents = count;
cout << numstudents << endl;








}
void AssignGrades(StudentType student[], int numstudents)
{


int testscore;


char grade;


for( int i = 0; i < NUM_STUDENTS; i++)
{
if(testscore >= 90 && testscore <=100)


grade = 'A';


else if(testscore >= 80 && testscore <90)


grade = 'B';


else if(testscore >= 70 && testscore <80)


grade = 'C';


else if(testscore >= 60 && testscore <70)


grade = 'D';


else


grade = 'F';
}


}
int HighestScore(const StudentType student[], int numstudents)
{
int Students = 6;////dummy


return Students;
}
void PrintNamesWithHighestScore(const StudentType student[], int numstudents)
{


}
void DisplayAllStudents(const StudentType student[], int numstudents)
{


}
void GetLowHighRangeValues(int& lowRange, int& highRange)
{


}


void DisplayStudentsInRange(const StudentType student[], int numStudents, int lownum, int highNum)
{


}


void SortStudentsByName(StudentType student[], int numStudents)
{


}


void SortStudentsByScore(StudentType student[], int numstudents)
{


}


Cheers & ty
Kiran