fix(guide): move guide to english directory

client/src/pages/guide/english/cplusplus/functions/index.md

@@ -0,0 +1,52 @@
+---
+title: Functions in C++
+---
+## Definition:
+
+A function is a group of statements that together perform a task. Every C++ program has at least one function, which is main().
+
+A function declaration tells the compiler about a function's name, return type, and parameters. A function definition provides the actual body of the function.
+
+## The general form of a C++ function definition:
+
+```cpp
+return_type function_name( parameter list )
+{
+   body of the function
+}
+```
+
+### Return type:
+A function may return a value. The return_type is the data type of the value the function returns. Some functions perform the desired operations without returning a value. In this case, the return_type is the keyword void.
+
+### Function name:
+This is the actual name of the function. The function name and the parameter list together constitute the function signature.
+
+### Parameters:
+A parameter is like a placeholder. When a function is invoked, you pass a value to the parameter. This value is referred to as actual parameter or argument. The parameter list refers to the type, order, and number of the parameters of a function. Parameters are optional; that is, a function may contain no parameters.
+
+### Function body:
+The function body contains a collection of statements that define what the function does.
+
+##Example:
+
+```cpp
+int max(int num1, int num2)
+{
+   // local variable declaration
+   int result;
+ 
+   if (num1 > num2)
+      result = num1;
+   else
+      result = num2;
+ 
+   return result; 
+}
+```
+
+## More Information
+
+* [TutorialsPoint](https://www.tutorialspoint.com/cplusplus/cpp_functions.htm)
+
+