Basics of functions:

A function is a sub program to perform a specific task.
OR
a group of instructions to perform specific task.

Along with main() it is possible to define our own functions by following these steps:
1. Function prototype or Function declaration.
2. Function call.
3. Function definition.

Function Prototype:

Giving information about the function such as return type, function name and arguments type to the compiler is known as function prototype; It is written at the declaration section.
Syntax:

< return_type > < function_name >( arguments_type );

Example:
int findsum(int a, int b);
float findsum(int a, int b);
void findsum(int a, int b);
int findsum(int a[], int size);
int findsum(int, int);

Function Definition:
Writing the actual code of the function in a block. It is at this stage the task of the function is defined. It is written after the main function.
Syntax:

< return_type >< function_name >(parameters)
{
 
}

Example:

int findsum(int a, int b)
{
 int sum;
 
 sum = a + b;
 return(sum);
}

Function Call:
It is a technique used to invoke a function.
Syntax:

[variable] < function_name >([arguments]);

Example:
res = findsum(10, 20);
res = findsum(x, y);
res = findsum();

Full Source Code:

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#include< iostream.h >
#include< conio.h >
 
void main()
{
  int Big(int x,int y);  // Prototype
 
  int a, b;
  clrscr();
 
  cout< <"Enter 2 numbers\n";
  cin>>a>>b;
 
  int res = Big(a, b);   // Function call
 
  cout< <"Biggest = "<<res;
  getch();
}
 
int Big(int x, int y)   // Function Definition
{
  return( x>y?x:y );
}

You must also watch these videos, before continuing with this program:
Find Biggest of 2 Numbers: C++
Biggest of Two Numbers Using Ternary Operator: C++

Video Tutorial: Biggest of 2 Numbers Using Function

Output:
Enter 2 numbers
420
305
Biggest = 420

Related posts:

1. Biggest of Two Numbers Using Ternary Operator: C++
2. Biggest of 3 Numbers Using Ternary Operator: C++
3. Find Biggest of 3 Numbers: C++

Find the sum of entered elements using dynamic memory allocation in c++.

In cpp, dynamic memory management can be done using the operators new and delete.
Operator new is used to allocate the memory during execution time or run time, the dynamically allocated memory can be freed / released using the operator delete.
Syntax:

< data_type >  < pointer_variable > = new < data_type >[size];

Full Source code

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#include< iostream .h>
#include< conio .h>
 
void main()
{
  int sum=0, N;
  clrscr();
 
  cout< <"Enter array size\n";
  cin>>N;
 
  int *a = new int[N];
  cout< <"\nEnter "<<N<<" integer numbers"<<endl;
  for(int i=0; i<N; i++)
   cin>>a[i];
 
   cout< <"Input array is.."<<endl;
   for(i=0; i<N; i++)
   {
    cout<<a[i]<<endl;
    sum = sum + a[i]; // sum += a[i];
   }
   cout<<"Total Sum: "<<sum;
 
   delete(a);
   getch();
}

We need not include any extra header file to perform dynamic memory allocation or de-allocation.

int *ptr = new int[N];

here it is mandatory to take pointer variable for dynamic memory allocation.

for de-allocation we use delete operator: delete(ptr);

NOTE:
Student *p = new Student[3];

where Student is a user defined data type, maybe structure or class.

Student *p = new Student; // This is for only 1 student.

Video Tutorial:(Basic) Find Sum Using Dynamic Memory Allocation

Output:
Enter array size
5
Enter 5 integer numbers
1
2
3
4
5
Input array is..
1
2
3
4
5
Total Sum: 15

Related posts:

1. Array Basics in C++ : Find Sum
2. Addition of 2 Numbers: C++
3. Reverse Given Number And Check For Palindrome: C++

Full Source code

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#include< iostream .h>
#include< conio .h>
 
void main()
{
  int num, rem, sum = 0, temp;
  clrscr();
 
  cout< <"Enter a number\n";
  cin>>num;
 
  temp = num;
 
  while( num )
  {
    rem = num % 10;
    num = num / 10;
    sum = sum * 10 + rem;
  }
 
cout< <"\nReversed Number: "<<sum<<endl;
 
  if( temp == sum )
   cout<<temp<<" is a palindrome";
  else
   cout<<temp<<" in NOT a palindrome";
 
  getch();
}

In this program we assign variable sum = 0 to avoid garbage values in sum before the calculation, which would result in wrong output.
We store the user entered value in temp, so that we can compare it with the final result, to determine whether the given number is palindrome or not.

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 while( num )
  {
    rem = num % 10;
    num = num / 10;
    sum = sum * 10 + rem;
  }

Here the loop executes until the value of num is zero.

If user enters 301, we apply the modulus to get the individual values.
Ex:
301 % 10 = 1
30 % 10 = 0
3 % 10 = 3

We get 301, 30 and 3 by dividing the original value by 10.
Ex:
301 user entered value.
301 / 10 = 30
30 / 10 = 3

Now the sum.

sum = sum * 10 + rem;

1 = 0 * 10 + 1
10 = 1 * 10 + 0
103 = 10 * 10 + 3

So the reverse of 301 is 103, which is not a palindrome.

Video Tutorial: Reverse Given Number And Check For Palindrome: C++

Output:
Enter a number
301
Reversed Number: 103
301 in NOT a palindrome

Related posts:

1. Find the Factorial of a Number: C++
2. Array Basics in C++ : Find Sum
3. Addition of 2 Numbers: C++

Array is a collection of homogeneous data items.

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
  //  int a[5] = { 1, 3, 2, 4, 5 }; declaration with initialization
 
  int a[5], sum = 0;
  clrscr();
 
  cout< <"Enter 5 numbers\n";
  for(int i=0; i&lt;5; i++)
   cin>>a[i];
 
  cout< <"Input array is..\n";
  for(i=0; i&lt;5; i++)
  {
   cout<<a[i]<<endl;
   sum = sum + a[i];  // sum += a[i];
  }
  cout<<"Sum of array elements: "<<sum;
 
  getch();
 
}

In this program we take input from the user and display the user entered numbers and find the sum of all the array elements and display it as well.

Elements are stored from the index number 0. i.e., if the array size is 5, the values will be stored in a[0], a[1], a[2], a[3], a[4];

Ex:
int a[5] = { 1, 3, 2, 4, 5 }; declaration with initialization
float a[5] = { 1.1, 2.0, 3.3, 1.3, 5.6 };

Video Tutorial: Array Basics in C++ : Find Sum

Output:
Enter 5 numbers
1
2
3
4
5
Input array is..
1
2
3
4
5
Sum of array elements: 15

Related posts:

1. Addition of 2 Numbers: C++
2. Find Biggest of 3 Numbers: C++
3. Find the Factorial of a Number: C++

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
  int fact = 1, N;
  clrscr();
 
  cout< <endl<<"Enter a number\n";
  cin>>N;
 
  for( int i=1; i< =N; i++ )
   fact = fact * i;  // OR fact *= i;
 
  cout<<endl<<endl<<"Factorial of "<<N<<" is "<<fact;
 
  getch();
}

Here the for loop stars from 1 and not 0. As anything multiplied by 0 would also be zero.

fact *= i; is the compact representation of fact = fact * i;

Video Tutorial: Factorial in cpp

Output:
Enter a number
5
Factorial of 5 is 120

Related posts:

1. Find Biggest of 3 Numbers: C++
2. Find Biggest of 2 Numbers: C++
3. Addition of 2 Numbers: C++

Before watching this video, please make sure to watch and understand this short video: Find Biggest of 3 Numbers: C++

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
	int a, b, c;
	clrscr();
 
	cout< <"Enter 3 no's\n";
	cin>>a>>b>>c;
 
	int big =  ( a>b && a>c )?a:(b>c?b:c);
	/*
	if( a > b && a > c )
	  big = a;
	else if( b > c )
	  big = b;
	else
	  big = c;
	*/
	cout< <"\nAmong "<<a<<" , "<<b<<" , "<<c<<" Biggest is "<<big;
	getch();
}

In this program we take 3 integer values from the user and using ternary operator decide the biggest of 3 numbers.

	int big =  ( a>b && a>c )?a:(b>c?b:c);

if ( a > b && a > c ) is true, then value of a will be stored in variable big; else ( b > c ? b : c ) will be evaluated. Here, if value of b is greater than c, value of b will be stored in variable big else value of c will be stored in the variable big.

Video Tutorial: Biggest of 3 Integer Numbers

Output
Enter 3 no’s
10
20
30
Among 10, 20, 30 Biggest is 30

Related posts:

1. Biggest of Two Numbers Using Ternary Operator: C++
2. Find Biggest of 3 Numbers: C++
3. Find Biggest of 2 Numbers: C++

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
	int a, b, c;
	clrscr();
 
	cout< <"Enter 3 no\n";
	cin>>a>>b>>c;
 
	int big;
 
	if( a > b )
	 big = a;
	else
	{
	 if( b > c )
	  big = b;
	 else
	  big = c;
	}
	cout< <"\nBiggest is: "<<big;
	getch();
}

In this program we get three integer variables from the user.
If value of variable a is bigger, then we store it inside the variable big; else we compare b with c. Now will store the biggest number inside the variable big.
Video Tutorial: Biggest of 3 Integer Numbers

Output
Enter 3 no’s
404
501
301
Biggest is: 501

Related posts:

1. Find Biggest of 2 Numbers: C++
2. Biggest of Two Numbers Using Ternary Operator: C++
3. Addition of 2 Numbers: C++

To find biggest of Two numbers using if-else control structure: Find Biggest of 2 Numbers: C++

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
 int a, b;
 clrscr();
 
 cout< <"Enter 2 numbers\n";
 cin>>a>>b;
 
 int big;
 
 big = a > b ? a : b;
 
/*
 if( a > b )
  big = a;
 else
  big = b;
*/
 
 cout< <"\nBig is: "<<big;
 
 getch();
}

In this program we take 2 integer values from the user and using ternary operator decide the biggest of 2 numbers.

	 big = a > b ? a : b;

if ( a > b ) is true, then value of a will be stored in variable big; else value of b will be stored in big.

Video Tutorial: Biggest of 2 Integer Numbers Using Ternary Operator

Output
Enter 3 no’s
404
302
Big is: 404

Related posts:

1. Find Biggest of 2 Numbers: C++
2. Addition of 2 Numbers: C++
3. Object Oriented Programming: C++

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
	int a, b;
	clrscr();
 
	cout< <"Enter 2 numbers\n";
	cin>>a>>b;
 
	int big;
 
	if( a > b )
	 big = a;
	else
	 big = b;
 
	cout< <endl<<"Among "<<a<<" and "<<b<<" biggest is "<<big;
 
	getch();
}

In this program we get two integer variables from the user.
If value of variable a is bigger, then we store it inside the variable big; else we store the value of variable b inside variable big.
Finally display the value of variable big which contains the biggest number amongst the two values entered by the user.

Video Tutorial: Biggest of 2 Integer Numbers

Output
Enter 2 numbers
-100
0
Among -100 and 0 biggest is 0

Related posts:

1. Addition of 2 Numbers: C++
2. Object Oriented Programming: C++
3. Simple Interest: C Program

Full Source Code

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#include<iostream .h>
#include<conio .h>
 
void main()
{
 
 int a, b;
 clrscr();
 
 cout< <"Enter two no\n";
 cin>>a>>b;
 
 int sum = a + b;
 
 cout< <endl<<"Sum is: "<<sum;
 
 getch();
 
}

We can declare variables anywhere in a cpp program.

Video Tutorial: Addition of 2 Integer Numbers

In this program we take input from the user, add it and then echo the result back to the screen.

Output
Enter two no
100
200

Sum is: 300

Related posts:

1. Using Constructors & Member Function to add two numbers: Java
2. Object Oriented Programming: C++
3. Simple Interest: C Program

Sample C Program:

#include<stdio.h>

void main()
{
  printf("Welcome To C");
}

Here stdio.h header file is included inorder to make use of printf and scanf functions.

Sample Cpp Program:

#include<iostream.h>

void main()
{
  cout<<"Welcome To Cpp";
}

Here iostream.h header file is included inorder to make use of cout and cin objects.

cout is an object of class ostream.
cin is an object of class istream.

Both these ostream and istream classes are present inside iostream.h file.

In both C and C++, execution of the program starts from main() function.

The difference is, printf and scanf are functions; while cout and cin are objects.

<< is called Insertion Operator. To show result on output window.
>> is called Extraction Operator. To get input from the user(keyboard).

Structures In C:

struct Student
{
  String name[];
  int age;
}s1;

To access members of structure:

s1.name[];
s1.age;

Video Tutorial: Basics of C++

Class In Cpp:

#include<iostream.h>
#include<conio.h>

class Student
{
  int a, b, c;

  public:
  void read() { cin>>a>>b>>c; }
  void show() { cout<<"\nEntered Numbers are "<<a<<" , "<<b<<" , "<<c; }
};

int main()
{
  A a;
  clrscr();

  cout<<"\nEnter 3 nums\n";

  a.read();
  a.show();

  getch();

}

member functions are accessed with the help of objects.

object.member

This way data binding is done and a level of security is imparted to the data.

Binding of Data and method into a single unit is called ENCAPSULATION.

Related posts:

1. First Java Program: Basic
2. Event Object: Javascript
3. Using Constructors & Member Function to add two numbers: Java

Video Tutorial: Colorful Text Output: C program

Full Source code: Colorful Text Output: C program C

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#include< stdio.h> /* Leave No space b/w < and stdio.h */
 
void main()
{
	int i;
	clrscr();
 
	for( i=0; i<=15; i++ )
	{
		textcolor(i);
		cprintf("Microsoft, Google, Yahoo, Oracle, eBay, PayPal \r\n");
	}
 
	getch();
 
}

textcolor() function takes color code as it’s parameter, and this color is taken by cprintf() function and the parameter(string) passed to cprintf is printed in the color given by textcolor() function.

OutPut:
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal
Microsoft, Google, Yahoo, Oracle, eBay, PayPal

Related posts:

1. Simple Interest: C Program
2. Write Data To Text File In C: Character by Character
3. First Java Program: Basic