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2011 BlueSignet LLC. All rights reserved.

Programming inC++Dynamic Memory Allocation & Exception

Handling

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

Works in a very similar way to calloc that we used in C

Created with

The operator new

Similar to malloc/calloc

Destroyed with The operator delete

Similar to free

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

#include

using namespace std;

int main(int argc, const char* argv[])

{

int SIZE = atoi(argv[1]);

int *integerArray = new int[SIZE];

for(int i = 0; i < SIZE; i++)

integerArray[i] = i;

for(int i = 0; i < SIZE; i++)

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

#include

using namespace std;

int main(int argc, const char* argv[])

{

int SIZE = atoi(argv[1]);

int *integerArray = new int[SIZE];

for(int i = 0; i < SIZE; i++)

integerArray[i] = i;

for(int i = 0; i < SIZE; i++)

cout dynmem.exe 3

integerArray

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

#include

using namespace std;

int main(int argc, const char* argv[])

{

int SIZE = atoi(argv[1]);

int *integerArray = new int[SIZE];

for(int i = 0; i < SIZE; i++)

integerArray[i] = i;

for(int i = 0; i < SIZE; i++)

cout dynmem.exe 3

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

#include

using namespace std;

int main(int argc, const char* argv[])

{

int SIZE = atoi(argv[1]);

int *integerArray = new int[SIZE];

for(int i = 0; i < SIZE; i++)

integerArray[i] = i;

for(int i = 0; i < SIZE; i++)

cout dynmem.exe 30

1

2

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

#include

using namespace std;

int main(int argc, const char* argv[])

{

int SIZE = atoi(argv[1]);

int *integerArray = new int[SIZE];

for(int i = 0; i < SIZE; i++)

integerArray[i] = i;

for(int i = 0; i < SIZE; i++)

cout dynmem.exe 30

1

2

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

#include

using namespace std;

int main(int argc, const char* argv[])

{

int SIZE = atoi(argv[1]);

int *integerArray = new int[SIZE];

for(int i = 0; i < SIZE; i++)

integerArray[i] = i;

for(int i = 0; i < SIZE; i++)

cout dynmem.exe 30

1

2

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

using namespace std;

int main()

{

string *str = new string;

*str = "This is my string";

delete str;

return 0;

}

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

using namespace std;

int main()

{

string *str = new string;

*str = "This is my string";

delete str;

return 0;

}

str

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

using namespace std;

int main()

{

string *str = new string;

*str = "This is my string";

delete str;

return 0;

}

01001

11011

str

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

using namespace std;

int main()

{

string *str = new string;

*str = "This is my string";

delete str;

return 0;

}

str

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

#include

using namespace std;

int main()

{

string *str = new string("This is my string");delete str;

return 0;

}

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

Although new and delete act like keywords, they are

actually operators

When new is called, memory is allocated from a memorypool called the Free Store

malloc and calloc use the Heap

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

Free Store Heap

Allocates with new Uses malloc / calloc

Deallocates with delete Uses free

Type Identification returns

a pointer with designatedtype

Returns a void pointer

Automatically handlesallocation size

Requires the block size tobe passed

Can be overwritten withmethod overridding

malloc / alloc / freemethods are all static

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Dynamic Memory Allocation

Generally, it is generally good practice to use heap forprimitive data types and Free Space for objects

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

This allows us to attempt potentially dangerous Plan Acode, and if anything fails we can setup a Plan B

So we try to execute a block of code, and if it fails wecatch the error

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

Exceptions allow us as programmers the chance to reactto an exceptional circumstance

When an exception is caught, we throw an exception,which transfers control to another section of code

Catching an exception requires a try block

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

int main(int argc, const char* argv[]){

try

{

throw new string("I am throwing an exception!!");

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

int main(int argc, const char* argv[]){

try

{

throw new string("I am throwing an exception!!");

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

voiddoSomething(int *param)

{

if(param ==NULL)throw new string("'param' cannot be null");

}

int main(int argc, const char* argv[])

{

int *intPointer =NULL;

try{

doSomething(intPointer);

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

voiddoSomething(int *param)

{

if(param ==

NULL)

throw new string("'param' cannot be null");

}

int main(int argc, const char* argv[])

{

int *intPointer =NULL;

try{

doSomething(intPointer);

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

voiddoSomething(int *param)

{

if(param ==NULL)

throw new string("'param' cannot be null");

}

int main(int argc, const char* argv[])

{

int *intPointer =NULL;

try{

doSomething(intPointer);

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

voiddoSomething(int *param)

{

if(param ==NULL)

throw new string("'param' cannot be null");

}

int main(int argc, const char* argv[])

{

int *intPointer =NULL;

try{

doSomething(intPointer);

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

using namespace std;

voiddoSomething(int *param)

{

if(param ==NULL)

throw new string("'param' cannot be null");

}

int main(int argc, const char* argv[])

{

int *intPointer =NULL;

try{

doSomething(intPointer);

}

catch (string *e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

It is generally good practice to put any dynamic memoryallocations within try blocks

If the memory cannot be allocated for some reason, thenyou can catch it

If this is not caught, your code will continue as if it

worked and either not work as expected or becomeunstable and crash

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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Programming in C++ 2011 BlueSignet LLC. All rights reserved.

Exception Handling

#include

#include

using namespace std;

int main(){

int* intArray;

try

{

intArray = new int[999999999];}

catch (exception &e)

{

cout

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2011 BlueSignet LLC. All rights reserved.

Programming in

C++The End?