C++ Programming Code Examples

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#define Directive in C++ Programming Language

#define Directive in C++

In the C++ Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. Macro definitions are not variables and cannot be changed by your program code like variables. You generally use this syntax when creating constants that represent numbers, strings or expressions. The syntax for creating a constant using #define in the C++ is: #define token value

Syntax for #define Directive in C++

#define macro-name replacement-text

• Using #define to create Macros Macros also follow the same structure as Symbolic Constants; however, Macros allow arguments to be included in the identifier:

#define SQUARE_AREA(l) ((l) * (l))

Unlike in functions, the argument here is enclosed in parenthesis in the identifier and does not have a type associated with it. Before compilation, the compiler will replace every instance of SQUARE_AREA(l) by ((l) * (l)), where l can be any expression. • Conditional Compilation There are several directives, which can be used to compile selective portions of your program's source code. This process is called conditional compilation. The conditional preprocessor construct is much like the 'if' selection structure. Consider the following preprocessor code:

#ifndef NULL #define NULL 0 #endif

/* #define directive in C++ language */ #include <bits/stdc++.h> using namespace std; void func1(); void func2(); #pragma startup func1 #pragma exit func2 void func1() { cout << "Inside func1()\n"; } void func2() { cout << "Inside func2()\n"; } int main() { void func1(); void func2(); cout << "Inside main()\n"; return 0; }

Demonstrate binary_search() in vector

Output file with ofstream

Inheriance for protected member

Using a class instead of struct.

Storing Class Objects with overloaded operators in a Vector

Heart Breaking Kid

If Else If Statement & Multiple Conditions

In this control structure we have only one 'if' and one 'else', however we can have multiple 'else if' blocks. This is how it looks: If none of the 'condition is true' then these statements

The remove copy if algorithm copies all elements from the range (first, last)

Calculate Area and Perimeter of Rectangle

To calculate "area and perimeter" of a square and rectangle in C++ Programming, you have to ask to the user to enter length and breadth of the rectangle and side length of the square

Use istream_iterator to loop through a string

Calculating Difference Between two Time

Ask to enter two time periods and these two periods are stored in structure variables t1 t2 respectively. The computeTimeDifference() Function calculates the Difference Between

Use generic vector to create vector of chars