Programming Forums > Application Development > C++

crawforddavid2006 · Jun 28th, 2006, 4:54 PM

How do I turn an in into a string in C++?

Klarre · Jun 28th, 2006, 5:09 PM

Try this function to convert from int to std::string.

#include <sstream>

template <class T>
std::string stringConverter(const T &value)
{
	std::stringstream stream;
	stream << value;

	return stream.str();
}

/Klarre

titaniumdecoy · Jun 28th, 2006, 6:17 PM

You can use atoi(string s) if it is available on your system.

DaWei · Jun 28th, 2006, 6:18 PM

Klarre has a good answer, but consider this: suppose you have the absolute value of 10 (decimal, the average number of fingers on two hands, assuming you don't mess around carelessly with a table saw). What is a string representing that? "10"? "Ten"? "diez"? "umpty-zillion"? You are in an area of (hopefully, somewhat cooperative) representation. There is no hard and fast answer.

Seif · Jun 28th, 2006, 7:02 PM

Quote:

Originally Posted by DaWei

the average number of fingers on two hands.

That the average number of fingers on mutant hands?

mrynit · Jun 28th, 2006, 7:30 PM

make sure its in the ascii range, or what ever system your using. look for the bounds.

Jessehk · Jun 28th, 2006, 8:08 PM

Just to be helpful (and to learn it myself), I though I'd devise the reverse function.

(Toggle Plain Text)

#include <string>
#include <sstream>
#include <stdexcept>
#include <iostream>

class ParseError : public std::invalid_argument {
    public:
        ParseError(const std::string &msg)
            : std::invalid_argument(msg) {
        }
};

template<typename T>
T parse_string(const std::string &input) throw(ParseError) {
    std::istringstream source(input);

    T result;
    if(!(source >> result))
        throw ParseError("Unable to retrieve data from input string.");
    else
        return result;
}

int main() {
    try {
        int n1 = parse_string<int>("3412");
        std::cout << n1 << std::endl;

        float n2 = parse_string<float>("3.14159");
        std::cout << n2 << std::endl;

        //should raise ParseError
        int n3 = parse_string<int>("abc");
        std::cout << n3 << std::endl;

    } catch(ParseError &pe) {
        std::cout << pe.what() << std::endl;
    }
}

crawforddavid2006 · Jun 28th, 2006, 9:31 PM

Well what i want is a loop that will turn the index number of that for loop into the string... ex. 10 = "10" not "Ten"

Prm753 · Jun 28th, 2006, 9:54 PM

Slightly-off-topic alert: This is not 100% C++, but it is an intresting function that I came across yesterday:

(Toggle Plain Text)

#include <iostream> 
#include <stdio.h>
int main() 
{
    char string[80];
    int number = 10;
    sprintf(string, // Char to which you want to put data in,
    "%i", // your string data, with the int specifed,
    number); // and of course, your int.
    std::cout << string << std::endl; 
    std::cin.get();
    return 0;
}

I wish it was that easy in C++.

angry_asian · Jun 28th, 2006, 10:10 PM

is that C prm753?

Jun 28th, 2006, 5:09 PM	#2
Klarre Game engine designer Join Date: May 2005 Location: Sweden Posts: 296 Rep Power: 4	Try this function to convert from int to std::string. (Toggle Plain Text) #include <sstream> template <class T> std::string stringConverter(const T &value) { std::stringstream stream; stream << value; return stream.str(); } #include <sstream> template <class T> std::string stringConverter(const T &value) { std::stringstream stream; stream << value; return stream.str(); } /Klarre __________________ http://www.klarre.se

Jun 28th, 2006, 6:18 PM	#4
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Klarre has a good answer, but consider this: suppose you have the absolute value of 10 (decimal, the average number of fingers on two hands, assuming you don't mess around carelessly with a table saw). What is a string representing that? "10"? "Ten"? "diez"? "umpty-zillion"? You are in an area of (hopefully, somewhat cooperative) representation. There is no hard and fast answer. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jun 28th, 2006, 7:30 PM	#6
mrynit Hobbyist Programmer Join Date: Mar 2006 Location: WA, USA Posts: 332 Rep Power: 3	make sure its in the ascii range, or what ever system your using. look for the bounds. __________________ i dont know much about programming but i try to help

Jun 28th, 2006, 8:08 PM	#7
Jessehk The Oblivious One Join Date: May 2005 Location: Ontario, Canada Posts: 639 Rep Power: 4	Just to be helpful (and to learn it myself), I though I'd devise the reverse function. (Toggle Plain Text) #include <string> #include <sstream> #include <stdexcept> #include <iostream> class ParseError : public std::invalid_argument { public: ParseError(const std::string &msg) : std::invalid_argument(msg) { } }; template<typename T> T parse_string(const std::string &input) throw(ParseError) { std::istringstream source(input); T result; if(!(source >> result)) throw ParseError("Unable to retrieve data from input string."); else return result; } int main() { try { int n1 = parse_string<int>("3412"); std::cout << n1 << std::endl; float n2 = parse_string<float>("3.14159"); std::cout << n2 << std::endl; //should raise ParseError int n3 = parse_string<int>("abc"); std::cout << n3 << std::endl; } catch(ParseError &pe) { std::cout << pe.what() << std::endl; } } #include <string> #include <sstream> #include <stdexcept> #include <iostream> class ParseError : public std::invalid_argument { public: ParseError(const std::string &msg) : std::invalid_argument(msg) { } }; template<typename T> T parse_string(const std::string &input) throw(ParseError) { std::istringstream source(input); T result; if(!(source >> result)) throw ParseError("Unable to retrieve data from input string."); else return result; } int main() { try { int n1 = parse_string<int>("3412"); std::cout << n1 << std::endl; float n2 = parse_string<float>("3.14159"); std::cout << n2 << std::endl; //should raise ParseError int n3 = parse_string<int>("abc"); std::cout << n3 << std::endl; } catch(ParseError &pe) { std::cout << pe.what() << std::endl; } } __________________ Dr. Zoidberg: [ecstatic] I'm going to a movie... with FRIENDS!

Jun 28th, 2006, 9:54 PM	#9
Prm753 Professional Programmer Join Date: Oct 2005 Location: United States Posts: 447 Rep Power: 3	Slightly-off-topic alert: This is not 100% C++, but it is an intresting function that I came across yesterday: (Toggle Plain Text) #include <iostream> #include <stdio.h> int main() { char string[80]; int number = 10; sprintf(string, // Char to which you want to put data in, "%i", // your string data, with the int specifed, number); // and of course, your int. std::cout << string << std::endl; std::cin.get(); return 0; } #include <iostream> #include <stdio.h> int main() { char string[80]; int number = 10; sprintf(string, // Char to which you want to put data in, "%i", // your string data, with the int specifed, number); // and of course, your int. std::cout << string << std::endl; std::cin.get(); return 0; } I wish it was that easy in C++. __________________ The world's first athletic computer geek! The home of PrProgramsStudios How not to post a question: <-- Please don't reply Last edited by Prm753; Jun 28th, 2006 at 10:12 PM.

Jun 28th, 2006, 6:17 PM	#3
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 839 Rep Power: 3	You can use atoi(string s) if it is available on your system.

Jun 28th, 2006, 10:10 PM	#10
angry_asian Hobbyist Programmer Join Date: Jun 2006 Location: at my computer desk Posts: 138 Rep Power: 3	is that C prm753?

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Programming Forums > Application Development > C++

Int to String