C++ Mechanics¶

Basic C++ program¶

Use of %%file magic
Use of #include to import libraries
Use of streams
Fully qualified names
Semi-colons and braces
Compilation and execution of binary

In [1]:

%%file hello01.cpp

#include <iostream>

int main() {
    std::cout << "Hello, world!" << std::endl;
}

Overwriting hello01.cpp

Compile¶

In [2]:

%%bash

g++ hello01.cpp -o hello01

Execute¶

In [3]:

%%bash

./hello01

Hello, world!

C equivalent¶

In [4]:

%%file hello01.c

#include <stdio.h>

int main() {
    printf("Hello, wolrd!\n");
}

Overwriting hello01.c

In [5]:

%%bash

gcc hello01.c -o hello_c

In [6]:

%%bash

./hello_c

Hello, wolrd!

Using qualified names¶

In [7]:

%%file hello02.cpp

#include <iostream>

using std::cout;
using std::endl;

int main() {
    cout << "Hello, world!" << endl;
}

Overwriting hello02.cpp

In [8]:

%%bash

g++ hello02.cpp -o hello02

In [9]:

%%bash

./hello02

Hello, world!

Using namespace¶

In [10]:

%%file hello03.cpp

#include <iostream>

using namespace std;

int main() {
    cout << "Hello, world!" << endl;
}

Overwriting hello03.cpp

In [11]:

%%bash

g++ hello03.cpp -o hello03

In [12]:

%%bash

./hello03

Hello, world!

Using a function¶

In [13]:

%%file hello04.cpp

#include <iostream>

using std::cout;
using std::endl;
using std::string;

string greet() {
    return "Hello, world!";
}

int main() {
    cout << greet() << endl;
}

Overwriting hello04.cpp

In [14]:

%%bash

g++ hello04.cpp -o hello04

In [15]:

%%bash

./hello04

Hello, world!

Separate compilation¶

In [16]:

%%file string_utils.hpp

#include <iostream>

std::string greet();

Overwriting string_utils.hpp

In [17]:

%%file string_utils.cpp

#include "string_utils.hpp"

std::string greet() {
    return "Hello, world!";
}

Overwriting string_utils.cpp

In [18]:

%%file hello05.cpp

#include <iostream>
#include "string_utils.hpp"

using std::cout;
using std::endl;

int main() {
    cout << greet() << endl;
}

Overwriting hello05.cpp

In [19]:

%%bash

g++ -c string_utils.cpp

In [20]:

%%bash

ls *\.o

string_utils.o

In [21]:

%%bash

g++ hello05.cpp string_utils.o -o hello05

In [22]:

%%bash

./hello05

Hello, world!

Separate compilation with a Makefile¶

In [23]:

%%file Makefile

hello05a:
    g++ hello05.cpp string_utils.o -o hello05a

string_utils.o:
    g++ -c string_utils.cpp

Overwriting Makefile

In [24]:

%%bash

make

make: `hello05a' is up to date.

In [25]:

%%bash

./hello05a

Hello, world!

Command line arguments¶

Also string streams and control flow.

In [26]:

%%file hello06.cpp

#include <iostream>
#include <sstream>

using std::cin;
using std::cout;
using std::endl;
using std::string;

string greet(string name) {
    std::stringstream s;
    s << "Hello " << name << "!";
    return s.str();
}

int main(int argc, char** argv) {
    if (argc > 1) {
        string name = argv[1];
        cout << greet(name) << endl;
    }
    else {
        cout << greet("world") << endl;
    }
}

Overwriting hello06.cpp

In [30]:

%%bash

g++ -std=c++11 hello06.cpp -o hello06

In [31]:

%%bash

./hello06

Hello world!

In [32]:

%%bash

./hello06 Cliburn

Hello Cliburn!

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