g++ default c++ version | Code Ease (2024)

Answered on: Wednesday 24 January, 2024 / Duration: 12 min read

Programming Language: C , Popularity :8/10

Solution 1:

Certainly! To determine the default C++ version used by g++ compiler, you can use the following command:

c
#include <iostream>
int main() {
 // Display the default C++ version
 std::cout << "__cplusplus value: " << __cplusplus << std::endl;
 return 0;
}

Compile and run the program using the following commands:

bash
g++ -o cpp_version cpp_version.cpp
./cpp_version

Now, let's break down the code:

1. #include : This line includes the input/output stream library for handling console output.
2. int main() { ... }: The main function, where the program execution begins.
3. std::cout << "__cplusplus value: " << __cplusplus << std::endl;: This line prints the value of the __cplusplus predefined macro, which indicates the version of the C++ standard that the compiler adheres to.
4. return 0;: Indicates successful program execution.

Compile the program and run it to get the output. The output will be the value of __cplusplus, which corresponds to the default C++ version used by the g++ compiler.

Keep in mind that the actual output value may vary based on the compiler and its version. The value __cplusplus is an integer that represents the C++ standard version. You can refer to C++ standard version mappings to interpret the output.

Note: The code and output may vary based on the compiler version and settings on your system.

Solution 2:

The g++ compiler is a command-line tool that can be used to compile C++ code. It is included with most Linux distributions and can also be installed on Windows and macOS.

The g++ compiler has a number of options that can be used to control the compilation process. These options can be used to specify the C++ standard that the compiler should use, the compiler flags that should be applied, and the output file that should be generated.

The default C++ version for g++ is the latest version that is supported by the compiler. This can be checked by running the following command:


g++ --version

This will output the version of g++ that is currently installed on the system.

For example, the following output shows that the default C++ version for g++ on a Linux system is 11:


g++ (Ubuntu 11.2.0-3ubuntu1~18.04.1) 11.2.0

The default C++ version for g++ can be changed by specifying the -std option. This option can be used to specify the C++ standard that the compiler should use.

The following table lists the available C++ standards for g++:

| Standard | Abbreviation |
|---|---|
| C++98 | c++98 |
| C++03 | c++03 |
| C++11 | c++11 |
| C++14 | c++14 |
| C++17 | c++17 |
| C++20 | c++20 |

For example, the following command would compile the code using the C++11 standard:


g++ -std=c++11 code.cpp -o output

The -o option can be used to specify the output file that should be generated. In this example, the output file will be called output.

Once the code has been compiled, it can be executed by running the following command:


./output

This will output the following message:


Hello world!

## Code Examples

The following code examples show how to use the g++ compiler to compile C++ code.

### Hello World

The following code shows a simple "Hello world" program written in C++:

c++
#include <iostream>
int main() {
 std::cout << "Hello world!" << std::endl;
 return 0;
}

To compile this code, use the following command:


g++ hello_world.cpp -o hello_world

This will create an executable file called hello_world. To run the program, use the following command:


./hello_world

This will output the following message:


Hello world!

### Fibonacci Sequence

The following code shows a program that prints out the Fibonacci sequence:

c++
#include <iostream>
int fibonacci(int n) {
 if (n == 0 || n == 1) {
 return n;
 } else {
 return fibonacci(n - 1) + fibonacci(n - 2);
 }
}
int main() {
 for (int i = 0; i < 10; i++) {
 std::cout << fibonacci(i) << std::endl;
 }
 return 0;
}

To compile this code, use the following command:

Solution 3:

The default C++ version used by the g++ compiler can vary depending on the version of the compiler and the operating system you are using. To check the default version of C++ used by your g++ compiler, you can use the following command in the terminal or command prompt:

css
g++ --version

This will display the version information of the g++ compiler, including the default C++ standard version.

For example, on a system with g++ version 9.3.0, the output may look like this:

c
g++ (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.