Why am I using single quotes around "|"?

Hi

I myself wrote the code below some months ago. But now I have forgotten much of C++ I learned so please help me to rejuvenate the memory. Why did I use single quotes around "|"? Shouldn't I have used double quotes? I know there is a reason for using single quotes but I can't recall it. Please help me. Thank you.

Code:

---

/* arranging the three numbers in ascending order assuming the numbers
are distinct */

// there would be six permutations in total

#include <iostream>
#include <cstdlib>

using namespace std;

int main()

{
        float A, B, C;
       
        cout << "enter the numbers A, B, C" << endl ;
       
        cout << "enter A = " ;
        cin >> A;
       
        cout << "enter B = " ;
        cin >> B;
       
        cout << "enter C = " ;
        cin >> C;
       
       
        if ( (A < B) && (B < C) )
            cout << "the ascending order is " << A << '|' << B << '|' << C << endl;
           
        else if ( (A < C) && (C < B) )
            cout << "the ascending order is " << A << '|' << C << '|' << B << endl;
           
        else if ( (B < A) && (A < C) )
            cout << "the ascending order is " << B << '|' << A << '|' << C << endl;
           
        else if ( (B < C) && (C < A) )
            cout << "the ascending order is " << B << '|' << C << '|' << A << endl;
           
        else if ( (C < A) && (A < B) )
            cout << "the ascending order is " << C << '|' << A << '|' << B << endl;
           
        else if ( (C < B) && (B < A) )
            cout << "the ascending order is " << C << '|' << B << '|' << A
            << endl;
   
        else
            cout << "Input error" << endl;
               
       
           
    system("pause");
   
    return 0;
   
}

---

'A' is a character that can be hardcoded into C++ , while "A" is a string literal which has an address, thus being more time consuming to fetch. And of course, the ostream could implement the output operator with single character as a simple put(), while the string equivalent would be something more complex.

The real question you should be asking yourself is, why aren't you using the STL? Keeping the C mentality of things while trying to learn C++ can be dangerous and result in very bad habits. One possible C++ solution for your program is:

Code:

---

#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>

int main(void){

        double number;
        std::vector<double>mynumbers; //"array" of numbers
       
        std::cout<<"Enter numbers(EOF to quit):";
        while(std::cin >> number){
                mynumbers.push_back(number);//add numbers to our vector
        }
       
        std::sort(mynumbers.begin(),mynumbers.end()); //sort numbers using STL

        /*output numbers to screen*/
        std::cout<<"Numbers in ascending order: ";
        std::copy(mynumbers.begin(), //output numbers in vector using STL iterators
                mynumbers.end(),
                std::ostream_iterator<double>(std::cout,"|"));

        return(0);
}

---

Quote:

---

Originally Posted by GReaper

'A' is a character that can be hardcoded into C++ , while "A" is a string literal which has an address, thus being more time consuming to fetch. And of course, the ostream could implement the output operator with single character as a simple put(), while the string equivalent would be something more complex.

---

The difference is so negligable that it isn't worth optimizing unless you can prove it's a bottleneck. Remember that premature optimization is evil™.
Also, in this case, it really doesn't matter if you use single quotes or double quotes.
A single quote represents a single character--which is exactly what '|' is--so it works. Nevertheless, "|" isn't wrong either, since it's a string with one character.

Thank you, all of you.

I think when I wrote that code I was simply proving to myself that I could also use '|' instead of "|" to the same effect. I usually do this just to teach myself.