13.Data Conversion.pptx

Data conversion

1. Type Conversions Different situations of data conversion between incompatible types 4 types of situation might arise in the data conversion: conversion from basic type to basic type Conversion from basic type to class type Conversion from class type to basic type Conversion from class type to class type Type Conversion 1

2. basic type to class type C onstructors perform this type of conversions int main() { int duration=85; time t=duration; t.display (); return 0; } Output: 1 hours 25 minutes Type Conversion class time { int hrs ; int mins; public: time() { } time(int t) { hrs =t/60; mins=t%60; } void display() { cout << hrs <<" hours"; cout <<mins<<" minutes"; } }; 2

3. class type to basic type constructor does not support this type of conversion So c++ allow us to define an overloaded casting operator that could be used to convert a class type data to basic type. It is also known as conversion function Overloaded casting operator actually overloads the built in casting operator. The casting operator function should satisfy following conditions It must be a class member It must not specify return type It must not have any arguments 3 Type Conversion

4. Here typename is any basic data type. This overloaded typecast operator function does not have any return type(not even void) Because the return type is the typename to which, the object is being converted. Moreover it does not take any parameter 4 Type Conversion Syntax:- operator typename () { ………… } Example: operator double() { …….. } operator int() { ……….. } Cont …

5. class type to basic type class time { int hrs; int mins ; public: time( int h,int m) {hrs=h; mins =m; } void display() { cout <<hrs<<" hours"; cout << mins <<" minutes"; } operator int () { return hrs*60+mins; } }; int main() { int duration; time t(3,20); t.display (); duration=t; cout<<"duration:"<<duration<<" minutes"; return 0; } Output: 3 hours20 minutes duration:200 minutes 5 Type Conversion

6. class type to class type Using conversion function in source class Using constructor in destination class A objA ; B objB ; objA = objB ; 6 Type Conversion Destination class Source class

7. class dollar { public: int doll; dollar(int x) { doll=x; } void show() { cout <<"Money dollars="<<doll<< endl ; } }; class rupee { double rs ; public: rupee(dollar d) { rs = d.doll *71.59; } void show() { cout <<"money in rupees:"<< rs ; } }; int main() { dollar d1(5); d1.show(); rupee r1=d1; r1.show(); return 0; } Output: Money dollars=5 money in rupees:357.95 7 Type Conversion constructor in destination class

8. class rupee { public: double rs ; rupee() { } rupee(double rs ) { this-> rs = rs ; } void show() { cout <<"money in rupees="<< rs ; } }; class dollar { public: int doll; dollar(int x) { doll=x; } operator rupee() { return rupee(doll*71.59); } void show() { cout <<"Money in dollars="<<doll<< endl ; } }; int main() { dollar d1(5); d1.show(); rupee r1=d1; r1.show(); return 0; } Output: Money in dollars=5 money in rupees=357.95 8 Type Conversion Using conversion function in source class