A function is declared globally above the main function, or within the main function. You can also declare a function inside another function in C++. In this article, you will learn to declare, define and call a local function.
Local Function Declaration
Like every other function, a local function must be declared within the body of another function. You must declare the return type, number of parameters and their type.
For example,
void account()
{
int total;
int bill1, bill2;
int add_bills(int , int );
//Initialization of variables
bill1 = 2000;
bill2 = 5000;
total = 0;
//Compute total bill amount
total = add_bills( bill, bill2);
//Print results
cout << "Total Amount =" << "" << total << endl;
}
//Definition of function add_bills()
int add_bills( int bill1, int bill2)
{
return(bill1 + bill2);
}The function add_bills() is a local function with proper declaration, definition and function call. The function add_bills() adds the bill1 and bill2 and return their sum.
You can add any number of local functions in your program as long as they do not violate the rules of C++ functions.
Recursive Functions
The recursive function is a special case of local function where a function calls itself several times until the programming problem is solved.
See the following figure for the general structure of a recursive function.
The function factorial calls itself recursively because each call to factorial will also call itself until the value of n becomes 0. The value of n is decreasing with each iteration.
Example Program:
/*Program to compute Nth factorial */
#include <cstdlib>
#include <iostream>
using namespace std;
int fact (int n)
{
unsigned int f;
if ((n == 0) || (n == 1))
return (n);
else
/* Compute factorial by Recursive calls */
f = n * fact (n - 1);
return (f);
}
main ()
{
int i, n;
/* Reading the number */
cout << "Enter the Number :";
cin >> n;
/* Printing results */
cout << "Factorial of Number" << n <<" is " << fact (n) << endl;
system ("PAUSE");
return 0;
}
Output:
Enter the Number: 5 Factorial of Number 5 is 120