This is a main function written with all codes in 'Xcode vs VS2013 Part1.'
Xcode shows three same error messages.
Line 160 & 171 & 187:
/Users/BB/Desktop/mac1/mac1/main.cpp:490:21: Invalid operands to binary expression ('List<double>::iterator' and 'List<double>::iterator')
// FILE: Driver.cpp
#include <iostream>
usingnamespace std;
template <typename T>
void cinNbr(T&); // enter a number from keyboard
void displayItems(const List<double>&);
void addItems(List<double>&);
void searchItem(const List<double>&);
void removeItem(List<double>&);
void removeCopies(List<double>&);
int main()
{
List<double> l1;
int menuChoice = 0;
bool quit = false;
while (!quit)
{
system("cls"); // clears the console screen
cout << "1. Show List contents\n";
cout << "2. Add item(s) to the List\n";
cout << "3. Search for an item in the List\n";
cout << "4. Withdraw single item from the List\n";
cout << "5. Withdraw all copies of an item from the List\n";
cout << "6. Exit the program\n\n";
cout << "What would you like to do? Select a number (1 - 6), then press Enter: ";
cinNbr(menuChoice);
switch (menuChoice)
{
case 1:
displayItems(l1);
system("pause"); // causes program to pause until user hits a key
break;
case 2:
cout << endl << "You chose to add value(s) to the List.\n";
cout << "Type the double(s) that will be stored,\n";
addItems(l1);
system("pause"); // causes program to pause until user hits a key
break;
case 3:
cout << endl << "You chose to search for a value in the List.\n";
cout << "Type the double to be searched:\n";
searchItem(l1);
system("pause"); // causes program to pause until user hits a key
break;
case 4:
cout << endl << "You chose to remove a value from the List,\n";
cout << "Type the double to be removed:\n";
removeItem(l1);
system("pause"); // causes program to pause until user hits a key
break;
case 5:
cout << endl << "You chose to remove all copies of a value from the List,\n";
cout << "Type the double to be completely removed:\n";
removeCopies(l1);
system("pause"); // causes program to pause until user hits a key
break;
case 6:
quit = true;
cout << endl;
break;
default:
cout << endl << "Invalid menu choice. Please try again.\n\n";
system("pause"); // causes program to pause until user hits a key
}
}
cout << "Closing...\n";
return 0;
}
template<typename T>
void cinNbr(T& var) // enter a number from keyboard
{
cin >> var;
while (cin.fail() || cin.get() != '\n') // if error encountered
{
cout << "Invalid entry! Please re-enter value: ";
cin.clear(); // clears any error flag
cin.ignore(80, '\n'); // clears input buffer
cin >> var;
}
cin.clear();
}
void displayItems(const List<double>& doubles)
{
if (doubles.size() == 0)
cout << "List empty!\n";
elseif (doubles.size() > 100)
{
cout << "List too long to be displayed!\n";
cout << "List size: " << doubles.size() << endl << endl;
}
else
{
cout << "Here are the contents:\n";
for (List<double>::const_iterator iLoc = doubles.begin(); iLoc != doubles.end(); iLoc++)
cout << (double)*iLoc << ", ";
cout << "\b\b \n"; // delete last space and comma
cout << "List size: " << doubles.size() << endl << endl;
}
}
void addItems(List<double>& doubles)
{
cout << "Press \"q\" when you are done:\n";
double itemInput;
while (true) // while valid double is entered
{
cin >> itemInput;
if (cin.fail() == false)
doubles.push_back(itemInput);
else
{
cin.clear(); // clear and ignore bad input
cin.ignore(80, '\n');
break; // invalid input
}
}
}
void searchItem(const List<double>& doubles)
{
if (doubles.size() == 0)
cout << "List empty!\n";
else
{
double itemInput;
cinNbr(itemInput);
size_t index = 0;
List<double>::const_iterator iLoc = doubles.begin();
while (iLoc != doubles.end())
{
if (*iLoc == itemInput)
{
cout << "Value " << itemInput << " found at node # " << index << endl;
break;
}
index++;
iLoc++;
}
if (iLoc == doubles.end())
cout << "Value " << itemInput << " not found!\n";
}
}
void removeItem(List<double>& doubles)
{
if (doubles.size() == 0)
cout << "List empty!\n";
else
{
double itemInput;
cinNbr(itemInput);
size_t index = 0;
List<double>::iterator iLoc = doubles.begin();
while (iLoc != doubles.end())
{
if (*iLoc == itemInput)
{
cout << "Value " << itemInput << " removed from node # " << index << endl;
doubles.erase(iLoc);
break;
}
index++;
iLoc++;
}
if (iLoc == doubles.end())
cout << "Value not found!\n";
}
}
void removeCopies(List<double>& doubles)
{
if (doubles.size() == 0)
cout << "List empty!\n";
else
{
double itemInput;
cinNbr(itemInput);
size_t index = 0;
size_t nbrDeleted = 0;
List<double>::iterator iLoc = doubles.begin();
while (iLoc != doubles.end())
{
if (*iLoc == itemInput)
{
cout << "Value " << *iLoc << " removed from node # " << index << endl;
iLoc = doubles.erase(iLoc);
nbrDeleted++;
}
else
iLoc++;
index++;
}
if (nbrDeleted == 0)
cout << "Value not found!\n";
}
}
I am sorry. I am new to this forum, so I didn't mean to do that.
My programming experience is so short (2 months) that I am not yet familiar with some concepts. Can you please explain why one should define an overload operator!=() ?
x != y is equivalent to a function call of the form operator!=(x, y), but this doesn't compile if an overload for operator!=() that takes parameters of the corresponding types, isn't defined. The language doesn't automatically generate relational operators for user-defined types.
