From 7e0f021a9aec35fd8e6725e87e3313b101d26f5e Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Sun, 27 Jan 2008 11:37:44 +0100 Subject: Initial import (2.0.2-6) --- reference/CPLUSPLUS/SYNTAX/class.html | 185 ++++++++++++++++++++++++++++++++++ 1 file changed, 185 insertions(+) create mode 100644 reference/CPLUSPLUS/SYNTAX/class.html (limited to 'reference/CPLUSPLUS/SYNTAX/class.html') diff --git a/reference/CPLUSPLUS/SYNTAX/class.html b/reference/CPLUSPLUS/SYNTAX/class.html new file mode 100644 index 0000000..45ec2af --- /dev/null +++ b/reference/CPLUSPLUS/SYNTAX/class.html @@ -0,0 +1,185 @@ +CLASS keyword + + + +

class keyword

+The concept of a class +allows you to +encapsulate + a set of related variables and only +allow access to them via predetermined functions. +

+ +The class keyword is used to declare the group of variables +and functions and the visability of the variables and functions. +Here is a basic example. + +

+ + + + +

+
+    class String 
+    {
+    public:
+  
+        void Set(char *InputStr)   // Declare an Access function
+        { 
+            strcpy(Str, InputStr); 
+        }
+
+    private:
+        
+        char Str[80];      // Declare a hidden variable.
+  
+    };
+

+ +

private: means that all variables and functions that + follow are only visable from within the class. + +
public: all functions and variables that follow this + statement can be accessed from outside the class. +

+ +Now we have declared a class called String we need to +use it. +

+ + + + +

+
+    main()
+    {
+        String Title;
+        
+        Title.Set("My First Masterpiece.");
+    }
+

+ +

+ +This code creates a String +object +called Title and then uses the Set member function +to initialise the value of Str. +

+In C++ the member function Set is also known as a +method +

+This is the strength +of object oriented programming, the ONLY way to change +Str is via the Set method. + +

+ +The final code example brings the last two examples together +ands a new method (called Get) that shows the contents of +Str + +

+ + + + +

+
+    #include <stdlib.h>
+    #include <iostream.h>               // Instead of stdio.h
+
+    class String 
+    {
+    public:
+  
+        void Set(char *InputStr)   // Declare an Access function
+        { 
+            strcpy(Str, InputStr); 
+        }
+        
+    char *Get(void)                // Declare an Access function
+        { 
+            return(Str); 
+        }
+        
+
+    private:
+        
+        char Str[80];      // Declare a hidden variable.
+  
+    };
+
+    main()
+    {
+        String Title;
+        
+        Title.Set("My First Masterpiece.");
+        
+        cout << Title.Get() << endl;
+    }
+

+ +

+ + +