Running C++ Programs at the Command Line

First, make sure you have g++ (the compiler), make (the build tool), and valgrind (the memory leak checker) installed using this command:

$ sudo apt-get install g++ make valgrind

You don’t need to run this on the lab computers: those programs should already be installed on the lab computers.

Second, save a copy of the files makefile (make sure to save this with the name makefile) and cmpt_error.h in the folder on your computer where you will be writing your program.

Third, using your favourite text editor (see below for some suggestions), save the following in a file named hello.cpp:

// hello.cpp
#include "cmpt_error.h"
#include <iostream>

int main() {
   std::cout << "Hello, CMPT 125!\n";
} // main

We will compile (or build) our programs using make, a standard Linux build tool. To compile your program ($ is the command-line prompt) type this:

$ make hello
g++  -std=c++14 -Wall -Wextra -Werror -Wfatal-errors -Wno-sign-compare -Wnon-virtual-dtor -g   hello.cpp   -o hello

Notice that this calls g++ with many options. These options come from makefile, so make sure it’s in the same folder as hello.cpp.

Assuming there are no errors, run the resulting program like this:

$ ./hello

Notice you must type ./ first.

To run a program with valgrind, type this:

$ valgrind ./hello

You will see a big log message when the program ends; it will usually tell you if there are any memory errors.

If you want to time how long it takes a program to run, you can use the time command like this:

$ time ./hello

Programming Text Editors and IDEs

You should use a good programming editor. Some popular, and relatively easy to user editors, are:

There are many other editors (e.g. emacs, vi, BlueFish) and IDEs (e.g. CodeBlocks) available.