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#include<iostream> // Provides cout, etc.
#include<fstream> // Provides open(), etc.
#include<cstring> // Provides strcpy(), etc.
#include<cctype> // Provides toupper()
using namespace std;
const int MAXNAMESIZE = 27; // Allows for 26 characters in name and null character '\o'
const int MAXCLASSSIZE = 50; // Maximum of 50 students in class
const char QUIT = 'Q'; // Allows user to quit program
struct student
{
char name[MAXNAMESIZE]; // Name of student
int student_number; // Student number of student
double gpa; // Grade point average of student
};
void explain_program(ostream& os);
// Program is explained in output stream os
void decimal_format(ostream& os);
// Decimals are formatted nicely in output stream os
void read_array_of_struct(istream& is, student s[], int& n, int capacity);
// Postcondition: n records have been read into s[] from input stream, and n<=capacity.
void write_array_of_struct(ostream& os, const student s[], int n);
// Precondition: s[] has n valid records
// Postcondition: The field values of these records are written to output stream os
void print_menu();
// Postcondition: The menu of options is printed to the screen
char get_choice();
// Postcondition: The users choice is returned
void sort_on_name(student s[], int n);
// Precondition: s[] has n valid records
// Postcondition: These records are sorted alphabetically
void sort_on_number(student s[], int n);
// Precondition: s[] has n valid records
// Postcondition: These records are sorted numerically by student number
void sort_on_gpa(student s[], int n);
// Precondition: s[] has n valid records
// Postcondition: These records are sorted numerically by GPA
double get_av(const student s[], int n);
// Precondition: s[] has n valid values
// Postcondition: The average GPA is returned
void write_av(ostream& os, double average);
// Precondition: gpa_av has a valid value
// Postcondition: gpa_av is written to output stream os
int main()
{
student s[MAXCLASSSIZE]; // Creates array elements s[0], s[1], s[MAXCLASSSIZE-1] of type student
int n; // Number of records read
char choice; // Menu choice from user
double gpa_av; // Average GPA of all students
ofstream fout; // Internal name for output file
ifstream fin; // Internal name for input file
explain_program(cout); // Explains program to user on the screen
// Open output file. If there is an error, exit the program
fout.open("stu.out");
if(fout.fail())
{
cout << "There was an error opening the output file.";
exit(1); // Exits the program
}
// Open input file. If there is an error, exit the program
fin.open("stu.in");
if(fin.fail())
{
cout << "There was an error opening the input file.";
exit(1); // Exits the program
}
// Format decimals on screen and in output file
decimal_format(cout);
decimal_format(fout);
// Document output file
fout << "Michael Sproul SMSV010388";
explain_program(fout);
// Read from input file stu.in into the array s[]
read_array_of_struct(fin,s,n,MAXCLASSSIZE);
// Print menu to the screen
print_menu();
// Get user choice for menu
choice = get_choice();
// Process until QUIT is entered
while(toupper(choice) != QUIT)
{
switch(toupper(choice))
{
case '0': print_menu(); // Prints menu to screen
break;
case '1': sort_on_name(s,n); // Sorts array alphabetically
cout << "\nSorted by name:\n\n";
write_array_of_struct(cout,s,n); // Write sorted array to screen
fout << "\nSorted by name:\n\n";
write_array_of_struct(fout,s,n); // Write sorted array to output file
break;
case '2': sort_on_number(s,n); // Sorts array numerically by student number
cout << "\nSorted by student number:\n\n";
write_array_of_struct(cout,s,n); // Write sorted array to screen
fout << "\nSorted by student number:\n\n";
write_array_of_struct(fout,s,n); // Write sorted array to output file
break;
case '3': sort_on_gpa(s,n); // Sorts array numerically by student number
cout << "\nSorted by GPA:\n\n";
write_array_of_struct(cout,s,n); // Write sorted array to screen
fout << "\nSorted by GPA:\n\n";
write_array_of_struct(fout,s,n); // Write sorted array to output file
break;
case '4': gpa_av = get_av(s,n); // Gets average of all GPA's
write_av(cout,gpa_av); // Writes average of all GPA's to screen
write_av(fout,gpa_av); // Writes average of all GPA's to output file
break;
default: // Inform user of invalid choice
cout << "\nSorry, " << choice << " is not a valid option";
cout << "\nPlease try again.\n";
}
// Get next choice from user
choice = get_choice();
}
// Close output and input files
fout.close();
fin.close();
return 0;
}
void explain_program(ostream& os)
{
os << "\n\nThis program gives a menu of choices, allowing you to sort by name,"
<< "student number, or grade point average, and allows you to see the "
<< "average GPA.\n\n";
}
void decimal_format(ostream& os)
{
os.setf(ios::fixed);
os.setf(ios::showpoint);
os.precision(2);
}
void read_array_of_struct(istream& is, student s[], int& n, int capacity)
{
char temp[MAXNAMESIZE], // Temporary storage for student name
ch; // Local variable used to read eoln character
n = 0; // Initiliazes n to a value of 0, as no records have been read
is.get(temp,MAXNAMESIZE);
while((!is.eof()) && (n < MAXNAMESIZE))
{
strcpy_s(s[n].name,temp); // Copy temp into s[n].name
is >> s[n].student_number; // Read student number
is >> s[n].gpa; // Read student GPA
is.get(ch); // Read eoln character
n++; // Add 1 to student count
is.get(temp,MAXNAMESIZE); // Read next name, if there is one
}
// Warn user if not all data was read from input file
if(!is.eof())
{
cout << "Warning - not all data was read."
<< "Last record read was " << s[capacity-1].name << endl;
}
}
void write_array_of_struct(ostream& os, const student s[], int n)
{
for(int i=0; i<n; i++)
{
os << s[i].name; // Prints student name
os.width(10); // Right justify by width of 10
os << s[i].student_number; // Prints student number
os.width(10); // Right justify by width of 10
os << s[i].gpa << endl; // Prints GPA
}
}
void print_menu()
{
cout << "\n0 - See menu again"
<< "\n1 - Sort by name"
<< "\n2 - Sort by student number"
<< "\n3 - Sort by GPA"
<< "\n4 - Find average GPA"
<< "\n" << QUIT << " - Quit this program\n\n";
}
char get_choice()
{
char c; // Local variable to store user choice
// Get choice from user
cout << "\nPlease enter a choice (0 to see menu):";
cin >> c;
return c;
}
void sort_on_name(student s[], int n)
{
student temp; // Local variable used to swap records
for(int i=0; i<n; i++)
{
for(int i=0; i<n; i++)
{
// If s[i].name is later in alphabet than s[i+1].name, swap the two records
if(strcmp(s[i].name,s[i+1].name) > 0)
{
temp = s[i];
s[i] = s[i+1];
s[i+1] = temp;
}
}
}
}
void sort_on_number(student s[], int n)
{
student temp; // Local variable used to swap records
for(int i=0; i<n; i++)
{
for(int i=0; i<n; i++)
{
// If s[i].student_number is greater than s[i+1].student_number, swap the records
if(s[i].student_number > s[i+1].student_number)
{
temp = s[i];
s[i] = s[i+1];
s[i+1] = temp;
}
}
}
}
void sort_on_gpa(student s[], int n)
{
student temp; // Local variable used to swap records
for(int i=0; i<n; i++)
{
for(int i=0; i<n; i++)
{
// If s[i].gpa is greater than s[i+1].gpa, swap the records
if(s[i].gpa > s[i+1].gpa)
{
temp = s[i];
s[i] = s[i+1];
s[i+1] = temp;
}
}
}
}
double get_av(const student s[], int n)
{
double av, // Local variable used to store average
sum = 0; // Sum of all GPA's
// Return value of 0 if no data is found
if(n == 0)
{
return 0;
}
for(int i=0; i<n; i++)
{
// Add GPA to sum of GPA's
sum = sum + s[i].gpa;
}
// Calculate the average GPA
av = sum / n;
return av;
}
void write_av(ostream& os, double average)
{
os << "The average GPA is " << average << endl << endl;
}
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