This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How to convert a number to string and vice versa in C++
I am using Qt Creator 2.5.0 and gcc 4.7 (Debian 4.7.2-4). I added "QMAKE_CXXFLAGS += -std=c++11" to .pro file. Everything seems to be OK, I used C++11 std::for_each and so on. But when I included "string" header and wanted to use stoi, i got the following error:
performer.cpp:336: error: 'std::string' has no member named 'stoi'
I found some questions related to MinGW and one more, to Eclipse CDT and they had their answers. But I use Linux, why it is NOT working here?
#include <iostream>
#include <string>
int main()
{
std::string test = "45";
int myint = stoi(test);
std::cout << myint << '\n';
}
or
#include <iostream>
#include <string>
using namespace std
int main()
{
string test = "45";
int myint = stoi(test);
cout << myint << '\n';
}
look at http://en.cppreference.com/w/cpp/string/basic_string/stol
std::stoi is a function at namespace scope, taking a string as its argument:
std::string s = "123";
int i = std::stoi(s);
From the error message, it looks like you expect it to be a member of string, invoked as s.stoi() (or perhaps std::string::stoi(s)); that is not the case. If that's not the problem, then please post the problematic code so we don't need to guess what's wrong with it.
Related
i keep getting this error. i know this is a c++ 11 function but it still isnt working with code blocks c++ compiler. am i using this function correctly of is it a problem with the codeblocks compiler. i tried changing the compiler. using the "have g++ follow the c++11 iso standard" i still keep getting this error. or getting the "stoi() does not exist in the current scope" error
#include <iostream>
#include <string>
using namespace std;
int main()
{
int test = 34;
cout << stoi(test);
}
stoi means "String To Int". It will read an int from a std::string (or std::wstring). See also the reference.
You were probably looking for the reverse std::to_string (reference). But you don't need either, there is no need to convert to string before printing:
#include <iostream>
int main()
{
int test = 34;
std::cout << test;
}
stoi means string to int. So it takes a string as an input.
This should work:
string test = "34"; cout << stoi(test);
I am trying to take a string and parse it into an int. I have read the many answers out there, and it seems that using stoi is the most up-to-date way. It appears to me that stoi uses std, but I am getting Function 'stoi' could not be resolved despitre using namespace std;
#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include<stdlib.h>
using namespace std;
int main(int argc, char* argv[]) {
string line = "";
string five = "5";
int number = stoi(five); //Error here with stoi
return 0;
}
Any ideas what is causing this?
Update:
I am using Eclipse. My flags are: -c -fmessage-length=0 -std=c++11
If you are using GCC or MINGW, then this is the answer:
std::stoi doesn't exist in g++ 4.6.1 on MinGW
This is a result of a non-standard declaration of vswprintf on
Windows. The GNU Standard Library defines
_GLIBCXX_HAVE_BROKEN_VSWPRINTF on this platform, which in turn disables the conversion functions you're attempting to use. You can
read more about this issue and macro here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37522.
If you're willing to modify the header files distributed with MinGW,
you may be able to work around this by removing the
!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) macro on line 2754 of
.../lib/gcc/mingw32/4.6.1/include/c++/bits/basic_string.h, and adding
it back around lines 2905 to 2965 (the lines that reference
std::vswprintf). You won't be able to use the std::to_wstring
functions, but many of the other conversion functions should be
available.
Please always provide platform and compiler information.
Toggle on C++11 support in your compiler flags. -std=c++11 for a recent gcc. For Eclipse, please refer to the corresponding question in the FAQ and this answer explains how to get rid of the remaining Eclipse warning.
If you are amenable to parsing an int another way, how about using an STL algorithm and a C++11 lambda expression?
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "12345";
int num = 0;
for_each(str.begin(), str.end(), [&num](char c){ num = 10 * num + (c - '0'); });
cout << str << " = " << num << endl;
}
I have included as a header. When I call the string I use std::string to fully specify where string is coming from. The error reads Zach was not declared in this scope. Could it by IDE or Compiler? I use eclipse with g++ on linux Ubuntu. The following is my source code.
#include <iostream>
#include <string>
int main(){
std::string name = Zach;
std::cout << name << std::endl;
}
Actually, it was a simple syntax error. Zach needed quotation marks around it.
This question already has answers here:
Problems with std::stoi, not working on MinGW GCC 4.7.2
(2 answers)
Closed 6 years ago.
I want to convert string to float with stof but it is not working
Also I was enabled c++ 11 in codeblocks
but give error me that "stof was not declared in this scope"
if I use of std::stof yet give error me that it is not member of std
Here is my code:
#include <iostream>
#include <string>
using namespace std;
int main()
{
string x;
x="23";
float y=stof(x)+2.1;
cout<<y;
return 0;
}
try this:
include <sstream>
std::stringstream ss;
ss << "23";
float f;
ss >> f;
You have declared y to be an integer.
By definition, integers do not have fractional or decimal parts.
When you add 2.1 it will truncate the decimal.
I am trying to take a string and parse it into an int. I have read the many answers out there, and it seems that using stoi is the most up-to-date way. It appears to me that stoi uses std, but I am getting Function 'stoi' could not be resolved despitre using namespace std;
#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include<stdlib.h>
using namespace std;
int main(int argc, char* argv[]) {
string line = "";
string five = "5";
int number = stoi(five); //Error here with stoi
return 0;
}
Any ideas what is causing this?
Update:
I am using Eclipse. My flags are: -c -fmessage-length=0 -std=c++11
If you are using GCC or MINGW, then this is the answer:
std::stoi doesn't exist in g++ 4.6.1 on MinGW
This is a result of a non-standard declaration of vswprintf on
Windows. The GNU Standard Library defines
_GLIBCXX_HAVE_BROKEN_VSWPRINTF on this platform, which in turn disables the conversion functions you're attempting to use. You can
read more about this issue and macro here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37522.
If you're willing to modify the header files distributed with MinGW,
you may be able to work around this by removing the
!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) macro on line 2754 of
.../lib/gcc/mingw32/4.6.1/include/c++/bits/basic_string.h, and adding
it back around lines 2905 to 2965 (the lines that reference
std::vswprintf). You won't be able to use the std::to_wstring
functions, but many of the other conversion functions should be
available.
Please always provide platform and compiler information.
Toggle on C++11 support in your compiler flags. -std=c++11 for a recent gcc. For Eclipse, please refer to the corresponding question in the FAQ and this answer explains how to get rid of the remaining Eclipse warning.
If you are amenable to parsing an int another way, how about using an STL algorithm and a C++11 lambda expression?
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "12345";
int num = 0;
for_each(str.begin(), str.end(), [&num](char c){ num = 10 * num + (c - '0'); });
cout << str << " = " << num << endl;
}