Array -klasse i C ++
Introduktionen af Array-klasse fra C ++ 11 har tilbudt et bedre alternativ til C-stil arrays. Fordelene ved array-klassen over C-stil array er:-
- Array-klasser kender sin egen størrelse, mens arrays i C-stil mangler denne egenskab. Så når vi passerer til funktioner, behøver vi ikke at videregive størrelsen på array som en separat parameter.
- Med C-stil matrix er der mere risiko for Array bliver forfaldet til en markør . Array -klasser forfaldes ikke til tip
- Array-klasser er generelt mere effektive lysvægt og pålidelige end C-stil arrays.
Operationer på array :-
1. at () :- Denne funktion bruges til at få adgang til elementerne i array.
2. få () :- Denne funktion bruges også til at få adgang til elementerne i array. Denne funktion er ikke medlem af Array -klassen, men overbelastet funktion fra klasse tuple.
3. operatør [] :- Dette ligner arrays i C-stil. Denne metode bruges også til at få adgang til array -elementer.
// C++ code to demonstrate working of array // at() and get() #include #include // for array at() #include // for get() using namespace std ; int main () { // Initializing the array elements array < int 6 > ar = { 1 2 3 4 5 6 }; // Printing array elements using at() cout < < 'The array elements are (using at()) : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar . at ( i ) < < ' ' ; cout < < endl ; // Printing array elements using get() cout < < 'The array elements are (using get()) : ' ; cout < < get < 0 > ( ar ) < < ' ' < < get < 1 > ( ar ) < < ' ' ; cout < < get < 2 > ( ar ) < < ' ' < < get < 3 > ( ar ) < < ' ' ; cout < < get < 4 > ( ar ) < < ' ' < < get < 5 > ( ar ) < < ' ' ; cout < < endl ; // Printing array elements using operator[] cout < < 'The array elements are (using operator[]) : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar [ i ] < < ' ' ; cout < < endl ; return 0 ; }
Produktion
The array elements are (using at()) : 1 2 3 4 5 6 The array elements are (using get()) : 1 2 3 4 5 6 The array elements are (using operator[]) : 1 2 3 4 5 6
4. foran () :- Dette returnerer henvisning til det første element af array.
5. Tilbage () :- Dette returnerer henvisning til det sidste element i array.
// C++ code to demonstrate working of // front() and back() #include #include // including header file to use stl array and there function using namespace std ; int main () { // Initializing the array elements array < int 6 > ar = { 1 2 3 4 5 6 }; // Printing first element of array cout < < 'First element of array is : ' ; int & a = ar . front (); cout < < a < < endl ; // Printing last element of array cout < < 'Last element of array is : ' ; int & b = ar . back (); cout < < b < < endl ; //change first and last element of array using these references a = 10 ; //now 1 change to 10 b = 60 ; //now 6 change to 60 //lets print array now cout < < 'array after updating first and last element n ' ; for ( auto x : ar ) { cout < < x < < ' ' ; } cout < < endl ; return 0 ; }
Produktion
First element of array is : 1 Last element of array is : 6 array after updating first and last element 10 2 3 4 5 60
6. størrelse () :- Det returnerer antallet af elementer i array. Dette er en egenskab, som C-stil arrays mangler.
7. max_size () :- Det returnerer det maksimale antal elementer, som Array kan indeholde, dvs. den størrelse, hvormed array er erklæret. Størrelsen () og max_size () returnerer den samme værdi.
// C++ code to demonstrate working of // size() and max_size() #include #include // for size() and max_size() using namespace std ; int main () { // Initializing the array elements array < int 6 > ar = { 1 2 3 4 5 6 }; // Printing number of array elements cout < < 'The number of array elements is : ' ; cout < < ar . size () < < endl ; // Printing maximum elements array can hold cout < < 'Maximum elements array can hold is : ' ; cout < < ar . max_size () < < endl ; return 0 ; }
Produktion
The number of array elements is : 6 Maximum elements array can hold is : 6
8. Swap () :- Swap () bytter alle elementer i en matrix med andre.
CPP // C++ code to demonstrate working of swap() #include #include // for swap() and array using namespace std ; int main () { // Initializing 1st array array < int 6 > ar = { 1 2 3 4 5 6 }; // Initializing 2nd array array < int 6 > ar1 = { 7 8 9 10 11 12 }; // Printing 1st and 2nd array before swapping cout < < 'The first array elements before swapping are : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar [ i ] < < ' ' ; cout < < endl ; cout < < 'The second array elements before swapping are : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar1 [ i ] < < ' ' ; cout < < endl ; // Swapping ar1 values with ar ar . swap ( ar1 ); // Printing 1st and 2nd array after swapping cout < < 'The first array elements after swapping are : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar [ i ] < < ' ' ; cout < < endl ; cout < < 'The second array elements after swapping are : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar1 [ i ] < < ' ' ; cout < < endl ; return 0 ; }
Produktion
The first array elements before swapping are : 1 2 3 4 5 6 The second array elements before swapping are : 7 8 9 10 11 12 The first array elements after swapping are : 7 8 9 10 11 12 The second array elements after swapping are : 1 2 3 4 5 6
9. tom () :- Denne funktion returnerer sandt, når matrixstørrelsen er nul ellers returnerer falsk.
10. Udfyld () :- Denne funktion bruges til at udfylde hele arrayet med en bestemt værdi.
// C++ code to demonstrate working of empty() // and fill() #include #include // for fill() and empty() using namespace std ; int main () { // Declaring 1st array array < int 6 > ar ; // Declaring 2nd array array < int 0 > ar1 ; // Checking size of array if it is empty ar1 . empty () ? cout < < 'Array empty' : cout < < 'Array not empty' ; cout < < endl ; // Filling array with 0 ar . fill ( 0 ); // Displaying array after filling cout < < 'Array after filling operation is : ' ; for ( int i = 0 ; i < 6 ; i ++ ) cout < < ar [ i ] < < ' ' ; return 0 ; }
Produktion
Array empty Array after filling operation is : 0 0 0 0 0 0
