Thread: 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);
}

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.