◆Unit : 1 User Defined Function

Function: When a program is divided into small parts, each part is known as function.

System Defined Function : A function which is defined by system is called system defined function.

User Defined Function: A function which is defined by user according to the requirement/need is called user defined function

Modularity : We can divide a large program into multiple small modules. Using functions, it is very easy to understand the program.

Code Reusability : If we create a function, we can call them multiple times as per our requirement.

Reduce the Size: Reduces the size of the code, duplicate set of statements are replaced by function calls.

Easy to find error: We can divide a large program into multiple small modules, it is easy to find out error from it.

Function Declaration: In this section, we declare a user defined function. We can declare a UDF before void main() function.

Function Calling: Once user defined function is created, we can call them many times as per our requirement.

Function Definition: Definition code is actual code of function. Function definition code has set of instruction to perform specific task.

Categories of Function:

1. No Argument No Return value (NANR)

2. No Argument With Return value (NAWR)

3. With Argument No Return value (WANR)

4 : With Argument With Return value (WAWR)

Nested Function: When there is a function inside another function is called nested function.

Recursion: When function calls itself then it is known as recursion.

◆ Unit : 2 Structure

Structure : Structure is a user defined data type that can store multiple data elements with different data types.

● struct keyword is used to declare a structure.

● We can access structure member using (.) dot operator

● we can assign/initialize structure variable using = (assignment operator)

array : Array is a collection of data elements with similar data type.

Union : Union is a user defined data type that has a collection of data elements with different data types.

● union keyword is used to create/declare a union.

◆ Unit : 3 pointer

Memory: Memory is sequential list of storage cells. 1 storage cell=1 byte.

Memory Address: Each cell has unique address which is known as Memory Address.

Pointer: Pointer is a variable that stores memory address of another variable as a value.

Pointer Advantages:

▪ Pointers are useful for accessing memory locations.

▪ Pointers provide an efficient way for accessing the elements of an array structure.

▪ Pointers are used for dynamic memory allocation as well as deallocation.

▪ Pointers are used to form complex data structures such as linked list, graph, tree,

Reference operator (&) : stores Memory address of variable

Dereference operator (*) : stores value of given memory address

Pointer Expression: We can perform arithmetic operations on Pointer variables using deference operators. We cannot perform arithmetic operations on memory address.

Scale Factor: When we perform increment or decrement operation on pointer variable then it will be automatically incremented or decremented by its byte size.

Character : It specifies single character represented in single quote like ‘A’, ‘a’, ‘4’, ‘*’ etc.

Call by Value: · When we pass actual value of variable in function, then it is known as call by value.

Call by Reference: · When we pass the address of the variable into the function call as the actual parameter, then it is known as call by reference.

◆ Unit : 4 C File management

Time Consuming : it takes lot of time to take inputs each time .

Lost of Data : Data will be lost when progarm is completed /terminated .

File : File is a place on disk where group of related data are stored .●

Operations on File

  1. Creation of a file

fopen() function : fopen() is a system defined function that is used to create a file or open an existing file.

fclose() function: This function is used to close the file that is being pointed by file pointer fp.

fputc() function: This function is used to write a single character into a file.

fgetc() function: This function is used to read a single character from a file.

fputs() function: This function is used to write a string into a file.

fgets() function: This function is used to read a string from a file.

fprintf() function: This function is used to write data into a file.

fscanf() function: This function is used to read data from a file.

ftell() function: This function is used to get current position of file pointer.

rewind() function: This function is used to move file pointer at beginning position.

fseek() function: This function is used to move the position of file pointer at specific position.

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