When a program becomes a process in memory, it is typically divided into four sections: stack, heap, text, and data. These sections represent different regions of memory allocated for different purposes during the execution of the process.
- Text: The machine instructions for the program are contained in the text segment, also known as the code segment. These instructions represent the executable code that the CPU interprets and runs. The text segment is usually read-only and fixed in size because the program’s code does not change during runtime. Examples of code stored in the text segment include function definitions, control structures, and other executable statements.
- Data: The program’s initialized global and static variables are found in the data section. Data in this segment is often initialized before the program begins execution and remains constant throughout its lifespan.
- Heap: The heap is a dynamically created memory segment that stores data that is allocated and deallocated during program execution. Common memory allocation functions include malloc(), calloc(), and realloc() in C and C++, as well as new and delete operators in Java and C++.
- Stack: The stack segment stores function call information, local variables, and other temporary data generated during the program’s execution. The stack runs on a last-in, first-out (LIFO) basis.