Upcoming SlideShare
×

# Presentation on template and exception

288 views

Published on

presentation on template and exception..
by syed sajid ali

Published in: Education, Technology
0 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

• Be the first to like this

Views
Total views
288
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
10
0
Likes
0
Embeds 0
No embeds

No notes for slide

### Presentation on template and exception

1. 1. 1
2. 2. 2
3. 3. 3
4. 4. Template concept can be use in two different concepts i. Function template ii. Class template 4
5. 5. The body of the function template is written in the same way in each case as function is written but the difference is that they can handle arguments and return value of different types. 5
6. 6. Function Template Template function: template <class T> void get(T a) { cout <<" value : "<<a; cin.get(); } void main() { int a=5; float b=4.3; get(a); get(b);  }  Simple function: void get(int a) { cout <<" value : "<<a; cin.get(); getch(); } void main() { int a=5; float b=4.3; get(a); get(b); } 6
7. 7. Continued…  Function Template:  Simple Function 7
8. 8. template <class T> T square(T value) { return value*value; } int main() { int a=5; float b=7.5; long c=50000900000; double d=784848.33; cout<<"square of int variable is : "<<square(a)<<endl; cout<<"square of long variable is : "<<square(b)<<endl; cout<<"square of long variable is : "<<square (c)<<endl; cout<<"square of double variable is : "<<square(d)<<endl; cin.get(); getch(); 8
9. 9. template<class t > void get( t x, t y , int c) { int sum; sum=x+y+c; cout<<sum; cin.get(); getch(); } void main() { int a=6; int b=9; int c=8; get(a,b,c); } 9
10. 10. Function Template template<class t, class v > void get(t x, v y ,int c) { v sum; sum=x+y+c; cout<<sum; cin.get(); getch(); } void main() { int a=6; float b=9.9; int c=8; get(a,b,c); } Output: 10
11. 11. Class template definition does not change Class template work for variable of all types instead of single basic type 11
12. 12. Class Template template <class t> class Basket { t first; t second; public: Basket (t a, t b) { first = a; second = b; } t Bat() { return (first > second?first:second); } }; //class end void main() { Basket <int> bo(6,8); cout<<bo.Bat()<<endl; Basket <float> b1(1.1,3.3); cout<<b1.Bat()<<endl; system ("pause"); } Output: 8 3.3 12
13. 13. Continued… If we write Basket <int> b(6.99,8.88); Instead of Basket <int> b(6,8); Output will be in integers i.e 8 13
14. 14. Class Template template <class t> class Basket { t first; t second; public: Basket (t a, t b) { first = a; second = b; } t Big(); }; //class end template <class t> t Basket <t>::Big() { return (first > second?first:second); } void main() { Basket <int> b(6,8); cout<<b.Big()<<endl; Basket <float> b1(4.1,1.1); cout<<b1.Big()<<endl; system ("pause"); } Output: 8 4.1 14
15. 15. Continued… template <class t> t Basket <t>::Big() { return (first > second?first:second); } The name Basket<t> is used to identify the class of which Big() is a member function . In a normal non-template member function the name Basket alone would suffice. Void Basket :: Big() { return (first > second?first:second); } 15
16. 16. Continued… int Basket<int>::Big() { return (first > second?first:second); } float Basket<float>::Big() { return (first > second?first:second); } 16
19. 19. An exception is a condition that occurs at execution time and make normal continuation of program impossible. When an exception occurs, the program must either terminate or jump to special code for handling the exception.  Divide by zero errors.  Accessing the element of an array beyond its range  Invalid input  Hard disk crash  Opening a non existent file 19
20. 20. The way of handling anomalous situations in a program-run is known as exception handling. Its advantage are:     Exception handling separate error-handling code from normal code. It clarifies the code and enhances readability Catch error s before it occurs. It makes for clear, robust and fault -tolerant program s. 20
21. 21.     Tries a block of code that may contain exception Throws an exception when one is detected Catches the exception and handles it Thus there are three concepts i. The try block ii.The throwing of the exception iii.The catch block 21
22. 22.  A block which includes the code that may generate the error(an exception) try { …. }    Can be followed by one or more catch blocks which handles the exception Control of the program passes from the statements in the try block ,to the appropriate catch block. Functions called try block, directly or indirectly, could test for the presence of the error 22
23. 23.    Used to indicate that an exception has occurred Will be caught by closest exception handler Syntax:if ( // error) { Throw error(); } 23
24. 24. Contain the exception handler.  These know what to do with the exceptiontypically print out that a type of error has occurred.  Catch blocks are typically located right after the try block that could throw the exception Syntax:catch() { ….. }  24
25. 25. 25
26. 26. Exceptions const int DivideByZero = 10; double divide(double x, double y) { if(y==0) { throw DivideByZero; } return x/y; } int main() { try { divide(10, 0); } catch(int i) { if(i==DivideByZero) { cout<<"Divide by zero error"; } cin.get(); }} Output:Divide by zero error 26
27. 27.             Class Aclass { Public: Class Anerror { }; Void func() { if(/*error condition*/) Throw Anerror(); } }; Int main() { Try { Aclass object1; Object1.fun(); } Catch (Aclass ::Anerror) //may cause error { //tell user about error } Return 0; } 27
28. 28. try { //try block } catch(type1 arg) { //catch block1 } catch(type2 arg) { //catch block2 } ……. ……. catch(typeN arg) { //catch blockN } 28
29. 29. Multiple Exceptions const int Max=3; class stack {private: int st[Max],top; public: class full {}; Class empty {}; stack() {top=-1; } void push(int var) { if(top>=Max-1) throw full(); st[++top]=var; } Int pop() {if(top<0) Throw empty(); Return st [top--]; } }; 29
30. 30. Continued… int main() {stack s1; try { s1.push(11); s1.push(22); s1.push(33); s1.push(44); S1.pop(); s1.pop(); S1.pop(); s1.pop(); } catch(stack::full) { cout<<"exception :stack full"<<endl; } Catch(stack::empty) { Cout<<“exception: stack empty”<<endl; } cin.get(); } 30
31. 31. class Distance { private: int feet; float inches; public: class InchesEx { }; Distance() { feet = 0; inches = 0.0; } Distance(int ft, float in) { if(in >= 12.0) throw InchesEx(); feet = ft; inches = in; } void getdist() { cout << "nEnter feet: "; cin >> feet; cout << "Enter inches: "; cin >> inches; if(inches >= 12.0) throw InchesEx(); } void showdist() { cout << feet << "’-" << inches; } }; 31
32. 32. Continued… int main() { try { Distance dist1(17, 3.5); Distance dist2; dist2.getdist(); cout << "ndist1 = "; dist1.showdist(); cout << "ndist2 = "; dist2.showdist(); } catch(Distance::InchesEx) { cout << "nInitialization error: "; cout<< "inches value is too large."; } cout << endl; return 0; } 32
33. 33. class Distance { private: int feet; float inches; public: class InchesEx { public: string origin; float iValue; InchesEx(string or, float in) { origin = or; iValue = in; } }; Distance() { feet = 0; inches = 0.0; } Distance(int ft, float in) { if(in >= 12.0) throw InchesEx("2-arg constructor", in); feet = ft; inches = in; } void getdist() { cout << "nEnter feet: "; cin >> feet; cout << "Enter inches: "; cin >> inches; 33
34. 34. Continued… if(inches >= 12.0) throw InchesEx("getdist() function", inches); } void showdist() { cout << feet << "’-" << inches; } }; void main() { try { Distance dist1(17, 3.5); Distance dist2; dist2.getdist(); cout << "ndist1 = "; dist1.showdist(); cout << "ndist2 = "; dist2.showdist(); } catch(Distance::InchesEx ix) { cout << "nInitialization error in " << ix.origin << ".n Inches value of " << ix.iValue << " is too large."; } 34
35. 35. class InchesEx { public: string origin; float iValue; InchesEx(string or, float in) { origin = or; iValue = in; } }; 35
36. 36.  Extracting data from the exception object int main() { const unsigned long SIZE = 10000; char* ptr; try { ptr = new char[SIZE]; } catch(bad_alloc) { cout << “nbad_alloc exception: can’t allocate memory.n”; return(1); } delete[] ptr; //deallocate memory cout << “nMemory use is successful.n”; return 0; } 36