Programming Forums > Application Development > C++

Master · Dec 23rd, 2005, 2:14 AM

I know this might sound like a dumb question, but how do i convert a const char to string;
ex

string collect;
const char str[] = "convert";
collect = convertostring(str); //what function is available for converting it

thanks for the help

nnxion · Dec 23rd, 2005, 2:25 AM

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#include <iostream>
#include <string>

using namespace std;

int main()
{
        string collect;
        const char str[] = "convert";
        collect = str;
        cout << str << endl;
        return 0;
}

This works for me.

Master · Dec 23rd, 2005, 1:19 PM

thanks, how can i convert a string to int
such as

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string num = "55"

nnxion · Dec 23rd, 2005, 2:44 PM

(atoi)num.c_str()

Master · Dec 23rd, 2005, 3:44 PM

Thanks again ^_^

para · Dec 23rd, 2005, 4:52 PM

(Toggle Plain Text)

std::string str = "123";
int i = atoi(str.c_str());

or

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std::string str = "123";
int i;
sscanf(str.c_str(), "%i", &i);

or

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#include <sstream>
...
std::string str = "123";
int i;

std::stringstream ss;
ss << str;
ss >> i;

atoi() is probably the easiest. There is also:

(Toggle Plain Text)

int atoi(const char *nptr);            /* convert string to int */
long atol(const char *nptr);           /* convert string to long */
long long atoll(const char *nptr);     /* convert string to long long */

Ooble · Dec 24th, 2005, 5:46 AM

While atoi is easiest for this specific circumstance, using a stringstream, as detailed in para's third example, would be best, as you can do pretty much everything with it:

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int i         = 41;
double d      = 2.194;
char c        = 'x';
std::string s = "meep";

std::stringstream ss;
ss << i << ' ' << d << ' ' << c << ' ' << s;
std::cout << ss.str();

This will print:

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41 2.194 x meep

Ooble · Dec 24th, 2005, 6:29 AM

M'kay, I answered a completely different question. Do what para said.

HaCkeR · Dec 24th, 2005, 7:04 AM

lol Ooble not like you to make a mistake

Ooble · Dec 24th, 2005, 2:20 PM

Au contraire, I always make at least one mistake. It's just that I usually notice it before the Edit buttons disappears.

Dec 23rd, 2005, 2:14 AM	#1
Master Programmer Join Date: Sep 2005 Location: GA Posts: 99 Rep Power: 3	A simple question I know this might sound like a dumb question, but how do i convert a const char to string; ex (Toggle Plain Text) string collect; const char str[] = "convert"; collect = convertostring(str); //what function is available for converting it string collect; const char str[] = "convert"; collect = convertostring(str); //what function is available for converting it thanks for the help

Dec 23rd, 2005, 2:25 AM	#2
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	(Toggle Plain Text) #include <iostream> #include <string> using namespace std; int main() { string collect; const char str[] = "convert"; collect = str; cout << str << endl; return 0; } #include <iostream> #include <string> using namespace std; int main() { string collect; const char str[] = "convert"; collect = str; cout << str << endl; return 0; } This works for me. __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

Dec 23rd, 2005, 1:19 PM	#3
Master Programmer Join Date: Sep 2005 Location: GA Posts: 99 Rep Power: 3	thanks, how can i convert a string to int such as (Toggle Plain Text) string num = "55" string num = "55"

Dec 23rd, 2005, 2:44 PM	#4
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	(atoi)num.c_str() __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

Dec 23rd, 2005, 4:52 PM	#6
para Programmer Join Date: Dec 2005 Posts: 65 Rep Power: 3	(Toggle Plain Text) std::string str = "123"; int i = atoi(str.c_str()); std::string str = "123"; int i = atoi(str.c_str()); or (Toggle Plain Text) std::string str = "123"; int i; sscanf(str.c_str(), "%i", &i); std::string str = "123"; int i; sscanf(str.c_str(), "%i", &i); or (Toggle Plain Text) #include <sstream> ... std::string str = "123"; int i; std::stringstream ss; ss << str; ss >> i; #include <sstream> ... std::string str = "123"; int i; std::stringstream ss; ss << str; ss >> i; atoi() is probably the easiest. There is also: (Toggle Plain Text) int atoi(const char nptr); / convert string to int / long atol(const char nptr); /* convert string to long / long long atoll(const char nptr); /* convert string to long long / int atoi(const char nptr); /* convert string to int / long atol(const char nptr); /* convert string to long / long long atoll(const char nptr); /* convert string to long long */

Dec 23rd, 2005, 3:44 PM	#5
Master Programmer Join Date: Sep 2005 Location: GA Posts: 99 Rep Power: 3	Thanks again ^_^

Dec 24th, 2005, 5:46 AM	#7
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	While atoi is easiest for this specific circumstance, using a stringstream, as detailed in para's third example, would be best, as you can do pretty much everything with it: (Toggle Plain Text) int i = 41; double d = 2.194; char c = 'x'; std::string s = "meep"; std::stringstream ss; ss << i << ' ' << d << ' ' << c << ' ' << s; std::cout << ss.str(); int i = 41; double d = 2.194; char c = 'x'; std::string s = "meep"; std::stringstream ss; ss << i << ' ' << d << ' ' << c << ' ' << s; std::cout << ss.str(); This will print: (Toggle Plain Text) 41 2.194 x meep 41 2.194 x meep __________________ Me :: You :: Them

Dec 24th, 2005, 6:29 AM	#8
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	M'kay, I answered a completely different question. Do what para said. __________________ Me :: You :: Them

Dec 24th, 2005, 7:04 AM	#9
HaCkeR Hobbyist Programmer Join Date: Nov 2005 Location: UK Posts: 131 Rep Power: 0	lol Ooble not like you to make a mistake

Dec 24th, 2005, 2:20 PM	#10
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Au contraire, I always make at least one mistake. It's just that I usually notice it before the Edit buttons disappears. __________________ Me :: You :: Them

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Programming Forums > Application Development > C++

A simple question