How can I upgrade C ++ to C11 on Ubuntu 14.10?

In your specific situation there is nothing to be updated. As per this your comment you use the version 4.9.1 of the GCC , which supports the standard #

C11 .

According to GCC Wiki :

  

GCC 4.9 Changes: "ISO C11 support is now at a level similar to ISO C99 support."

Basically, you have to change the itoa function to std::to_string .

The real problem is to use the itoa function, it is not a standard function and not works in GCC on Linux ( at least in my case ). A minimum, complete, and verifiable example of this problem might be:

#include <stdio.h>
#include <stdlib.h>

int main (){
  int i;
  char buffer [10];
  printf ("Digite um número: ");
  scanf ("%d", &i);
  itoa (i, buffer, 10);
  printf ("String: %s\n", buffer);
  return 0;
}

When you compile, the following message will appear:

$ g++ -std=c++11 main.cpp -o exemplo1
main.cpp: In function ‘int main()’:
main.cpp:9:22: error: ‘itoa’ was not declared in this scope
   itoa (i, buffer, 10);
                      ^
$

Note : If the above command returns the error to_string 'is not a member of std , change -std=c++11 to -std=c++0x .

According to this IBM article , the std::to_string function is a convenient way to implement what the itoa function does. The same code, but for C ++, can be done like this:

#include <iostream>
#include <string>

int main(){
    int numero;
    std::cout << "Digite um número: " << std::endl;
    std::cin >> numero;
    std::string str = std::to_string(numero);
    std::cout << "String " << str << std::endl;
}

If you use Code :: Blocks as the IDE, and the to_string 'message is not a member of std (or similar) to appear for you, do the following:

• Click Settings ➝ Compiler..
• Navigate to the Compiler Settings ➝ Compiler Flags

• Check the option Have g ++ follow the coming C ++ 0x ISO language standard -std = c ++ 0x .

  

Compileandrunthecodeagain.Thismaynotworkinspecificsituations,butitusuallydoes.

Update

Attheendoftheday,theproblemwassolvedusingthe sprintf function, which can be used following way:

#include <string>
#include <iostream>

#define LIMITE 10

int main(){
    int numero = 1234567890;
    char str[LIMITE];
    sprintf(str, "%d", numero);
    std::cout << str << std::endl;
}

Note: It is not always recommended to use sprintf , in this specific case it is known to in advance the size of the variable numero , so there are no major problems in using it, but in certain situations where the size that a variable can assume (whether reading a file or user input) is not known, to avoid < a href="https://en.stackoverflow.com/q/52555/6454"> leaks use the snprintf .