Type conversion functions

1. 1. Converting by assignment
operator
2. Using cast operator
Syntax:
(cast_type) expression;
or
cast_type (expression);
09/04/131 VIT - SCSE
Type Conversion
#include<iostream.h>
#include<conio.h>
void main()
{
char ch='A';
int x;
x=(int)ch;
cout<<x;
getch();
}

2. Enum Types
The enum keyword automatically enumerates a list of words
by assigning them values 0,1,2,3,4, and so on.
The general form of enum is:
enum variable_name{ list of constants separated by commas };
e.g:
enum day{sun,mon,tue,wed,thu,fri,sat};
09/04/132 VIT - SCSE

3. # include<iostream.h>
enum day{sun,mon,tue,wed,thu,fri,sat};
void main( )
{
day d1, d2,d3;
d1 = mon;
d2 = fri;
int diff = d2 – d1;
cout<<"days between = "<<diff<<endl;
if(d1<d2)
cout<< "day1 comes before day2n";
}
09/04/133 VIT - SCSE

4. Functions
A function groups a number of program statements into a
unit and gives it a name.
This unit can then be invoked from other parts of the
program.
It is used to reduce program size.
The main advantages of using a function are:
1. Easy to write a correct small function
2. Easy to read, write and debug a function
3. Easier to maintain or modify such a function
4. It can be called any number of times in any place with
different parameters
09/04/134 VIT - SCSE

5. 09/04/135 VIT - SCSE
The Function Declaration
The Function Definition
Function Calling

6. Return statement
The keyword return is used to terminate function and return
a value to its caller.
The return statement may also be used to exit a function
without returning a value.
The general form of the return statement is.
 return;
 return ( expression);
09/04/136 VIT - SCSE

7. //using multiple return
statements in a function
# include<iostream.h>
void main()
{
float maximum( float, float, float);
float x,y,z,max;
cout<<"Enter three numbers";
cin>>x>>y>>z;
max = maximum(x,y,z);
cout<<"maximum"<<max;
}
float maximum(float a,float b,float c)
{
09/04/137 VIT - SCSE
if(a>b)
{
if(a>c)
return (a);
else
return (c);
}
else
{
if(b>c)
return (b);
else
return (c);
}
}

8. Types of functions
A function is invoked without passing any formal
argument does not return any value to the calling
portion.
A function is invoked with formal argument and
does not return any value to the calling portion.
A function is invoked with formal argument and
returns back a value to the calling environment.
09/04/138 VIT - SCSE

9. Function Arguments
The arguments can be classified into two groups:
1. Actual argument
2. Formal argument
Local and Global variable
09/04/139 VIT - SCSE

10. A function which calls itself directly or indirectly again and again is
known as the recursive function.
09/04/1310 VIT - SCSE
Recursive function
int sum(int n)
{
int value=0;
if(n= = 0)
return(value);
else
value = n+sum(n-1);
return(value);
}
# include<iostream.h>
void main()
{
int sum(int);
int n,temp;
cout<<"Enter any integer
number"<<endl;
cin>>n;
temp = sum(n);
cout<<"value = "<<n<<"and its
sum ="<< temp;
}

11. E.x: void sum(int a,int b,int c=6,int d=10);
09/04/1311 VIT - SCSE
Default arguments
void sum(int a1,int
a2,int a3,int a4)
{
int temp;
temp = a1+a2+a3+a4;
cout<<"sum="<<temp;
}
// default argument declaration
# include<iostream.h>
void sum(int a,int b,int c=6,int d=10);
//default argument
initialization
void main()
{
int a,b,c,d;
cout<<"enter any two
numbers"<<endl;
cin>>a>>b;
sum(a,b); //sum of default values
}

12. 09/04/1312 VIT - SCSE
Function Overloading
cout<<add(5,10);
cout<<add(15,10.0);
cout<<add(12.5,7.5);
cout<<add(5.10,15);
cout<<add(0.75,5);
int add(int a,int b);
int add(int a,int b,int c);
double add(double x,double y);
double add(int p,double q);
double add(double p,int q);

13. 09/04/1313 VIT - SCSE
Function Overloading
double volume(double r,int h)
{
return(3.14519*r*r*h);
}
long volume(long l,int b,int h)
{
return (1*b*h);
}
#include<iostream.h>
int volume(int);
double volume(double,int);
long volume(long,int,int);
main()
{
cout<<volume(10)<< endl;
cout<<volume(2.5,8)<<endl;
cout<<volume(100L,75,15);
getch();
return 0;
}
int volume(int s)
{
return (s*s*s);
}