A source code writen in C/C++ is stored in storage. When we compile it, the system creates an executable file, which is also stored in storage. When we run the program, it is loaded into memory and then executed. So, what kind of structure does a program have once it is loaded into memory?
The memory layout of a C/C++ program is structured into text segment, initialized data segment, uninitialized data segment, heap and stack.
Text Segment
At the lowest memory addresses, the program’s code is stored.
Initialized Data Segment (DS)
This is where global and static variables are stored, provided that they are initialized with a non-zero value by the programmer.
Unintialized Data Segment (BSS)
This is where global and static variables that are either uninitialized or initialized to zero are stored.
Heap and Stack
The stack is a region of memory that is automatically allocated and follows a LIFO (Last In, First Out) structure. On the other hand, heap is manually allocated by programmer.