C Programming: Functions

Study Notes

A function is a block of code that can be called multiple times from different parts of a program
Functions can take arguments and return values
Functions can be classified into:
- Library functions (e.g. printf, scanf) provided by the C standard library
- User-defined functions created by the programmer

Function declaration syntax:

eturn_type function_name(data_type arg1, data_type arg2, ...);

Error handling is the process of detecting and responding to errors or exceptions in a program
C provides several error handling mechanisms, including:
- Error codes: returned by functions to indicate errors
- Error messages: printed to the console to indicate errors
- Exception handling: using setjmp and longjmp functions to handle exceptions
Common error handling functions:
- perror(): prints an error message to the console
- strerror(): returns a string describing an error code

A function is a block of code that can be called multiple times from different parts of a program
Functions can take arguments and return values
There are two types of functions: library functions (e.g. printf, scanf) and user-defined functions
The function declaration syntax is: return_type function_name(data_type arg1, data_type arg2,...);
The function call syntax is: function_name(arg1, arg2,...);

An array is a collection of elements of the same data type stored in contiguous memory locations
Elements can be accessed using an index (subscript)
Array declaration syntax is: data_type array_name[size];

A structure is a collection of elements of different data types stored in a single unit
Elements can be accessed using the dot (.) operator
Structure declaration syntax is: struct struct_name { data_type element1; data_type element2;...};

Error handling is the process of detecting and responding to errors or exceptions in a program
C provides several error handling mechanisms, including error codes, error messages, and exception handling
Error handling functions include perror() and strerror()
perror() prints an error message to the console
strerror() returns a string describing an error code

File input/output (I/O) is the process of reading and writing data to files
C provides several file I/O functions, including fopen(), fclose(), fread(), fwrite(), fscanf(), and fprintf()
File modes include "r" for read mode, "w" for write mode, "a" for append mode, "r+" for read and write mode, "w+" for read and write mode (truncates file if it exists), and "a+" for read and append mode

A pointer is a variable that stores the memory address of another variable
Pointer declaration syntax is: data_type *pointer_name;
Pointer operations include dereferencing and obtaining the memory address of a variable
Dereferencing is done using the asterisk symbol: *pointer_name;
Obtaining the memory address of a variable is done using the ampersand symbol: &variable_name;
Pointer arithmetic includes incrementing, decrementing, and adding an integer to a pointer