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Wrote most of the C++ code for the c to c++ tutorial blog post.

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jrtechs 6 years ago
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      entries/programming/Learning-C++-for-C-Developers.md
  2. +566
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      entries/programming/c-to-c++-tutorial.md
  3. +5
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      server.js

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entries/programming/Learning-C++-for-C-Developers.md View File

@ -1,103 +0,0 @@
## Namespaces
## Input/Output
## Global Variable
```c++
using namespace std;
#include <iostream>
double a = 128;
int main ()
{
double a = 256;
cout << "Local a: " << a << endl;
cout << "Global a: " << ::a << endl;
return 0;
}
```
## Multiple Names for a Variable
## Passing Variables by Reference
```c++
void change (double &r, double s)
{
r = 100;
s = 200;
}
```
## Functions Returning Variables not Values
## Static Variables
## Namespaces
```c++
namespace foo
{
int a, b;
}
//in main
first::a = 2;
```
## Inline -- similar to Macros
## Exceptions
## Default Parameters for Functions
## Function Overloading
## Operator Overloading
## Functions with Generic Parameter Types
## Replacement for malloc and free
## Struct Functions
# Classes
## Class Constructor and De-constructor
## Scope
## Method Prototypes for Classes
## This keyword
## Class Inheritance
## "Abstract" Classes
# File IO
## Writing to File
## Reading From File

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entries/programming/c-to-c++-tutorial.md View File

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## Namespaces
## Input/Output
```
using namespace std;
#include <iostream>
int main()
{
cout << "Hello World" << endl;
int a;
cin << a;
cout << "You entered: << a << endl;
return 0;
}
```
## Global Variable
```c++
using namespace std;
#include <iostream>
double bar = 64;
int main ()
{
double bar = 12;
cout << "Local bar: " << bar << endl;
cout << "Global bar: " << ::bar << endl;
return 0;
}
```
## Multiple Names for a Variable/Aliasing
```c++
double pi = 3.145;
double &x = pi; //pi is x
x = 2.1;
cout << "pi: " << pi << " x: " << x << endl; // prints pi: 2.1 x: 2.1
```
## Passing Variables by Reference
```c++
void change (double &r, double s)
{
r = 100;
s = 200;
}
int main()
{
int x = 1;
int y = 2;
cout << x << ", " << y << endl;
change(x, y);
cout << x << ", " << y << endl;
return 0;
}
```
Same code in C.
```c
void change(double *r, double s)
{
*r = 100;
s = 200;
}
int main()
{
int x = 1;
int y = 2;
printf("%d, %d", x, y);
change(&x, y);
printf("%d, %d", x, y);
return 0;
}
```
## Functions Returning Variables not Values
A reference can be used to have a function return a variable -- not a value.
```c++
using namespace std;
#include <iostream>
int &smallest (int &x, int &y)
{
if (x < y)
return x;
else
return y;
}
int main ()
{
int k = 33;
int m = 2;
cout << "k: " << k << " m: " << m << endl; // prints k: 33 m: 2
smallest (k, m) = 10;
cout << "k: " << k << " m: " << m << endl; // prints k: 33 m: 10
return 0;
}
```
## Namespaces
```c++
namespace foo
{
int a, b;
}
int main()
{
first::a = 2;
return 0;
}
```
## Inline -- similar to Macros
Inline can be used to replace a function which contains very simple logic -- no
for loops, etc. Like a macro, this will be inserted everywhere the code is used; a
draw back to inline methods is that the compiled source will be larger. But, they
typically run faster.
```c++
inline int square(int x)
{
return x * y;
}
int main()
{
int k = 4;
cout << square(k) << endl; //prints 4
return 0;
}
```
## Exceptions
```c++
int x;
cout << "Type a number: ";
cin >> x;
cout << endl;
try
{
if(a > 150)
throw 150;
if(a < 15)
throw 15;
throw a % 2;
}
catch(int result)
{
cout << result << " was thrown." << endl;
}
```
## Default Parameters for Functions
```c++
double multiply(double x, double y = 5)
{
return x * y;
}
int main()
{
cout << multiply(4) << endl; // 20
cout << multiply(4, 4) endl; // 15
return 0;
}
```
## Function Overloading
```c++
double add(double x)
{
return x + x;
}
double add(double x, double y)
{
return x + y;
}
int add(int x, int y)
{
return x + y;
}
int main()
{
cout << multiply(4) << endl; // 20
cout << multiply(4, 4) endl; // 15
return 0;
}
```
## Operator Overloading
```c++
using namespace std;
#include <iostream>
struct tuple
{
int x;
int y;
};
tuple operator + (int a, vector b)
{
vector r;
r.x = a + b.x;
r.y = a + b.y;
return r;
}
int main ()
{
tuple k, m; // No need to type "struct tuple"
// also no need to typedef
k.x = 3;
k.y = 6;
m = 2 + k; // Voodoo witchcraft
cout << "(" << m.x << ", " << m.y << ")" << endl;
return 0;
}
```
## Functions with Generic Parameter Types
```c++
template <class ttype>
ttype max (ttype a, ttype b)
{
ttype r;
r = a;
if (b < a) r = b;
return r;
}
template <class type1, class type2>
type1 maximum (type1 a, type2 b)
{
type1 r, b_converted;
r = a;
b_converted = (type1) b;
if (b_converted > a)
r = b_converted;
return r;
}
```
## Replacement for malloc and free
```c++
int i*;
i = new int;
*i = 55;
delete i;
i = new int[15];
i[0] = 99;
delete i;
```
## Struct Functions
```c++
struct tuple
{
int i;
int x;
int sum()
{
return i + x;
}
};
```
# Classes
```c++
class Tuple
{
public:
int i;
int x;
int sum()
{
return i + x;
}
};
```
## Class Constructor and De-constructor
```c++
class Tuple
{
public:
int i;
int x;
Tuple(int i1, int i2)
{
i = i1;
x = i2;
}
~Tuple()
{
//delete any memory you have!
}
int sum()
{
return i + x;
}
};
// in main
Tuple t (12, 14);
Tuple tt = new Tuple(12, 15);
```
## Scope
```c++
class Person
{
protected:
int age;
string name;
public:
Person(int age, string name)
{
}
~Person()
{
}
private:
void increaseAge()
{
age++;
}
}
```
## This keyword
```c++
class Person
{
protected:
int age;
string name;
public:
Person(int age, string name)
{
this->age = age;
strcpy(this->name, name);
}
~Person()
{
}
private:
void increaseAge()
{
age++;
}
}
```
## Class Inheritance
```c++
class Tuple
{
protected:
int x;
int y;
public:
Tuple(int i1, int i2)
{
x = i1;
y = i2;
}
virtual int sum()
{
return i + x;
}
};
class Triple: public Tuple
{
protected:
int x;
int y;
int z;
public:
Triple(int i1, int i2, i3): Tuple(i1, i2)
{
z = i3;
}
int sum()
{
return x + y + z;
}
};
```
## "Abstract" Classes
```c++
class Animal
{
public:
virtual void speak()=0;
}
class Cat: public Animal
{
public:
void speak()
{
cout << "Meow" << endl;
}
}
```
## Method Prototypes for Classes
```c++
class Cat: public Animal
{
public:
void speak()
{
cout << "Meow" << endl;
}
int fly(); //method prototype
}
// Off in a header file or something
int Cat::fly()
{
return 42;
}
```
# File IO
## Reading From File
```c++
#include <fstream>
//in main or somewhere
fstream f;
char c;
f.open("p022_names.txt", ios::in);
while(!f.eof())
{
f.get(c);
cout << c;
}
f.close();
```
## Writing to File
```c++
#include <fstream>
//in main or somewhere
fstream f;
char c;
f.open("p022_names.txt", ios::out);
f << "stuff in the file " << endl;
int i = 4;
f << i << " this is also in the text file" << endl;
f.close();
```

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server.js View File

@ -108,11 +108,11 @@ app.use(function(request, res)
try
{
var ip = (request.headers['x-forwarded-for'] || '').split(',').pop() ||
request.connection.remoteAddress ||
request.socket.remoteAddress ||
request.connection.socket.remoteAddress;
sql.logTraffic(ip, filename);
var getClientAddress = (request.headers['x-forwarded-for'] || '').split(',')[0]
|| request.connection.remoteAddress;
console.log(getClientAddress);
sql.logTraffic(getClientAddress, filename);
}
catch (e)
{

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