cplusplus:pointers_4_slides
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cplusplus:pointers_4_slides [2021/10/24 02:49] – [The new operator] mithat | cplusplus:pointers_4_slides [2021/10/24 02:59] – [Example] mithat | ||
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* reserves a block of memory to hold the specified %%< | * reserves a block of memory to hold the specified %%< | ||
* returns the base address of that block. | * returns the base address of that block. | ||
+ | * optional parenthesis around ''< | ||
<code cpp> | <code cpp> | ||
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double *myPtr, *yourPtr; | double *myPtr, *yourPtr; | ||
- | myPtr = new (double); | + | myPtr = new double; |
- | yourPtr = new (double); | + | yourPtr = new double; |
cout << "Enter a number: "; | cout << "Enter a number: "; | ||
Line 108: | Line 109: | ||
void ninetynine() | void ninetynine() | ||
{ | { | ||
- | int localVar = 99; | + | int localVar = 99; // localVar is destroyed at end of fcn call |
cout << localVar << endl; | cout << localVar << endl; | ||
} | } | ||
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void ninetynine() | void ninetynine() | ||
{ | { | ||
- | int *localPtr = new int; | + | int *localPtr = nullptr; |
+ | | ||
*localPtr = 99; | *localPtr = 99; | ||
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* Memory leaks, no matter how small, are bad programming practice. | * Memory leaks, no matter how small, are bad programming practice. | ||
* Can be fixed by the proper use of **deallocation**: | * Can be fixed by the proper use of **deallocation**: | ||
- | * Deallocation of dynamically allocated storage does not happen automatically. | + | |
* You must explicitly (i.e., manually) deallocate the memory. | * You must explicitly (i.e., manually) deallocate the memory. | ||
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int *myPtr = new int; | int *myPtr = new int; | ||
... | ... | ||
- | delete myPtr; // deallocates block pointed to by localPtr. | + | delete myPtr; // deallocates block pointed to by myPtr. |
</ | </ | ||
cplusplus/pointers_4_slides.txt · Last modified: 2021/10/24 03:02 by mithat