To do list.

Collect example codes for
1. pthread
2. wgl initialization
3. egl initialization
4. opengl example

STL string samples.

Here's some STL string sample codes.
STL string class is much more convenient compared to old character pointer(or array) string.
However, it has its own weakness; the slower performance.
So, you should use STL string carefully.

---

Sample 1 - setup for STL string

// Headers.
//
#include <string> // for STL string.
#include <iostream> // for cout.

// STL classes are defined in "std" namespace.
//
using namespace std;

int main(void)
{
// Create a string variable with name "str". The storage for "hello" is automatically
// managed by the string class.
//
string str = "hello";

// output to console.
// "hello" will be displayed.
//
cout << str << endl;

return 0;
}

---

Sample 2. String copy.

// Headers.
//
#include <string> // for STL string.
#include <iostream> // for cout.

// STL classes are defined in "std" namespace.
//
using namespace std;

int main(void)
{
// Create a string variable with name "str".
string str = "hello";

// Create a new string variable with name "str2" copying the content of "str".
string str2 = str;

// output to console.
// will display "hello".
//
cout << str2 << endl;

return 0;
}

---

Sample 3. String concatenation.

// Headers.
//
#include <string> // for STL string.
#include <iostream> // for cout.

// STL classes are defined in "std" namespace.
//
using namespace std;

int main(void)
{
// Create a string variable with name "str". The storage for "hello" is automatically
// managed by the string class.
//
string str = "hello";

// append another string " world" to the end of "hello".
//
str += " " + "world";

// output to console.
// will display "hello world".
//
cout << str << endl;

return 0;
}

Note - this kind of string contenation can cause performance degradation since it involves several memory allocations and copys.

---

Sample 4 - "char *" string and "string" string.

// Headers.
//
#include <string> // for STL string.
#include <iostream> // for cout.

// STL classes are defined in "std" namespace.
//
using namespace std;

int main(void)
{
// Old C style string.
char *oldStr = "hello";

// You can create new string variable from old C style string constant.
string str = string(oldStr);

// append another string " world" to the end of "hello".
//
str += " world";

// output to console.
//
cout << str << endl;

return 0;
}