#include < iostream >
using namespace std;
inline float simple interest(float p1 ,float n1, float r1)
{
float si 1=(p 1*n 1*r1)/100;
return(si 1);
}
int main ( )
{
flot si, p,n,r
cout < < "\n Enter the Principle Amount Rs. :";
cin > > p;
cout < <"\n Enter the Number of Years :";
cin > > n;
cout < < "\n Enter the Rate of Interest :";
cin > > r;
si=simple interest(p,n,r);
cout < < "\n The Simple Interest = Rs."< return 0;
}
Output:
Enter the Principle Amount Rs. :50000
Enter the Number of Years :5
Enter the Rate of Interest :7
The Simple Interest = Rs. 17500

C++ program can contain any number of functions. But, it must always hav. only one main ( ) function to begin the program execution. We can write the definitions of fun dons in any order as we wish. We can define the main( ) function first and all other functions after that or we can define all the needed functions prior to main( ), Like a variable declaration, a function must be declared before it is used in the program. The declaration statement may be given outside the main( ) function.

The prototype above provides the following information to the compiler:
1. The return value of the function is of type long.
2. fact is the name of the function
3. the function is called with two arguments
The first argument is of int data type.
The second argument is of double data type.
int display(int, int)//function prototype//
The above function prototype provides details about the return data type, the name of the function, and a list of formal parameters or arguments.

The srand( ) function in C++ seeds the pseudo random number generator used by the rand( ) function. The seed for rand( ) function is 1 by default. It means that if no srand( ) is called before rand( ), the rand( ) function behaves as if it was seeded with srand(1). The srand( ) function takes an unsigned integer as its parameter which is used as seed by the rand( ) function. It is defined in< cstdlib >or < stdlib.h >header file.
#include< iostream >
#include< cstdlib.h >
using namespace std;
int main ( )
{
int random = rand( ); 1* No srand( ) calls before rand( ), so seed = 1*/
cout < < "\nSeed = 1, Random number =" < < random;
srand(10);
/* Seed = 10 */
random = rand ( );
cout < < "\n\n Seed = 10, Random number ="< < random;
return 0;
}
Output:
Seed = 1, Random number = 41
Seed = 10, Random number = 71

The scope operator reveals the hidden scope of a variable. The scope resolution operator (::) is used for the following purposes. To access a Global variable when there is a Local variable with same name. An example using Scope Resolution Operator.
// Program to show that we can access a global variable
// using scope resolution operator :: when there is a local
// variable with same name //
#include< iostream >
using namespace std;
int x=45; // Global Variable x
int main()
{
int x = 10; // Local Variable x
cout << "\nValue of global x is " << ::x;
cout << "\nValue oflocal x is" << x;
return 0;
}
Output:
Value of global x is 45 .
Value of local x is 10

Inline functions can be used to reduce the overheads like STACKS for small function definition.
An inline function looks like normal function in the source file but inserts the function's code directly into the calling program. To make a function inline, one has to insert the keyword inline in the function header.
Syntax:
inline retuntype functionname( datatype parametemame1, ... datatype parametemameN)
Advantages of inline functions: Inline functions execute faster but requires more memory space. Reduce the complexity of using STACKS.
Example:
#include< iostream >
using namespace std;
inline float simpleinterest(float.pl, float nl, float rl)
{
float si 1=(p1*n1*r1)/100;
retumf si 1);
}
intmain0
{
float si.p,n,r;
cout<< "\nEnter the Principal Amount Rs.:";
cin> p;
cout<< "\nEnter the Number of Years :";
cin<< n;
cout << "\nEnter the Rate ofInterest :";
cin>> r:
si=simpleinterest(p,n,r) ;
cout<< "\nThe Simple Interest = Rs."<< si;
return 0;
}