C++ Notes: Dynamic Allocation of Arrays
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Saved by 2 people (0 private), first by anonymouse user on 2008-04-23
- Gowthad on 2009-06-06 - Tags allocation , arrays , c++
- Totorototo on 2008-04-23 - Tags allocation , arrays , c++
Public Sticky notes
Allocate an array with code>new
When the desired size of an array is known, allocate memory for it
with the new operator and save the address of that memory
in the pointer. Remember: Pointers may be subscripted just as arrays are.
The example below reads in a number and allocates that size array.
int* a = NULL; // Pointer to int, initialize to nothing.
int n; // Size needed for array
cin >> n; // Read in the size
a = new int[n]; // Allocate n ints and save ptr in a.
for (int i=0; i<n; i++) {
a[i] = 0; // Initialize all elements to zero.
}
. . . // Use a as a normal array
delete [] a; // When done, free memory pointed to by a.
a = NULL; // Clear a to prevent using invalid memory reference.
Highlighted by totorototo
Allocate an array with code>new
When the desired size of an array is known, allocate memory for it
with the new operator and save the address of that memory
in the pointer. Remember: Pointers may be subscripted just as arrays are.
The example below reads in a number and allocates that size array.
int* a = NULL; // Pointer to int, initialize to nothing.
int n; // Size needed for array
cin >> n; // Read in the size
a = new int[n]; // Allocate n ints and save ptr in a.
for (int i=0; i<n; i++) {
a[i] = 0; // Initialize all elements to zero.
}
. . . // Use a as a normal array
delete [] a; // When done, free memory pointed to by a.
a = NULL; // Clear a to prevent using invalid memory reference.
Highlighted by gowthad
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