Execution Flow of C Program

The execution of a C program typically involves the following steps

• Preprocessing: Before a C program is compiled, it goes through a preprocessing step where the preprocessor directive #include is used to include header files and the preprocessor directive #define is used to define macros.

  It also removes comments from the source code. The preprocessor generates a modified version of the source code, which is then fed to the compiler.

• Compilation: The C compiler converts the preprocessed source code into object code, which is machine-readable code that can be executed on a computer.

  During this step, the compiler checks for syntax errors and generates error messages if it finds any.

• Linking: In this step, the linker combines the object code generated by the compiler with any necessary libraries to create an executable file.

  The linker resolves any unresolved symbols in the object code by looking for their definitions in the libraries.

• Loading: When the program is run, it is loaded into memory by the operating system. The program's instructions are then executed by the processor.

• Execution: The program begins executing at the main function and then follows the flow of control determined by the statements in the program.

• When the main() function returns, the program terminates, and the operating system releases the memory allocated to the program.

Execution Flow

It is important to note that the execution flow of a C program can be influenced by various factors such as compiler optimizations, program logic, and user input. Understanding the execution flow is essential for debugging and optimizing C programs.