2. Disclaimer: This presentation is prepared by trainees of
baabtra as a part of mentoring program. This is not official
document of baabtra –Mentoring Partner
Baabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt .
Ltd

3. STACK AND HEAP
ARJUN S R
Arjun.sr007@gmail.com
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ryavartham
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07
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4. PROGRAM ADDRESS SPACE
• Any program you run has, associated with it, some
memory which is divided into:
– Code Segment
– Data Segment (Holds Global Data)
– Stack (where the local variables and other temporary information is
stored)
– Heap

5. Continue…..
Code Segment
Data Segment
Stack
HeapThe Heap grows downwards
The Stack grows upwards

6. STACK
• Stack – a linear data structure in which items are added and
removed in last-in, first-out order.
• In most modern computer systems, each thread has a
reserved region of memory referred to as its stack.
• When a function executes, it may add some of its state data to
the top of the stack; when the function exits it is responsible
for removing that data from the stack.
• The place where arguments of a function call are stored
• The place where local data of called function is allocated
• Automatic data

7. • The place where called function leaves result for calling
function(return address).
• Supports recursive function calls.
• All modern programming languages require a stack.
• All modern processors provide a designated stack pointer
register.
• All modern process address spaces provide room for a stack
• It has mainly two operations
push-process of insert values into stack
pop –Process of remove a value from the stack

8. Process Address Spaces
0x00000000
0xFFFFFFFF
Virtual
address space
program code
(text)
static data
heap
(dynamically allocated)
stack
(dynamically allocated)
PC
SP

9. HEAP
• The heap is used to store variables dynamically
allocated by the application (malloc). The data
section initialized at compile-time.
• Dynamic variables are never initialized by the
compiler, so it is a good practice to initialize it.
Eg:
int *p;
p=new int;
*p=0;

10. • A place for allocating memory that is not part of last-
in, first-out discipline
• I.e., dynamically allocated data structures that
survive function calls
• E.g., strings in C
• new objects in C++, Java, etc.
• The size of the heap is set on application startup, but
can grow as space is needed (the allocator requests
more memory from the operating system)
• Used on demand to allocate a block of data for use
by the program.

11. HEAP AND STACK EXAMPLE
int main() {
pointT pt;
double total = 0.0;
pt.x = 1;
pt.y = 2;
int *array = new int[5];
Nonsense(array, pt, total);
return 0;
}
void Nonsense(int list[], pointT pt, double & sum) {
pointT *pptr = new pointT;
list[1] = pt.x;
sum += pt.y;
}

12. HEAP stack
1000 pptr FFDO
1004 sum FFD4
1008 pt FFD8
100C list FFE0
1010
1014 array FFE8
1018 total FFEC
FFF0
pt FFF4
FFF8
1
1004
FFEC
1
2
1000
1000
2.0
1
2

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