Programming C Introduction (Variables, Data types, Specifiers, Identifiers) || Programming C Notes Unit 1

Question: What is Psuedo Code ?

Psuedo Code: Pseudocode is a language-agnostic method for describing algorithms using simple English phrases. It's a helpful tool for programmers to develop algorithms without getting bogged down in specific programming language syntax. It allows for a rough design of a solution based on the problem explanation, helping to clarify the logic before diving into coding. With pseudocode, programmers can focus on the problem-solving process rather than the intricacies of coding syntax.

The general guidelines for developing pseudocodes are:

•  Statements should be written in English and should be programming language independent.
• Steps of the pseudocodes must be understandable.
• It should be concise.
• Each instruction should be written in a separate list and each statement in pseudocode should express just one action for the computer.
• The keywords like READ, PRINT etc should be write in capi- tal letter.
•  Each set of instruction should written from top to bottom, with only one entry and one exit.

 

About Algorithm.

Ans: An algorithm is a step-by-step solution to a problem, written in simple English-like statements. It consists of explicit and unambiguous steps that, when followed with given initial conditions, produce a desired output and terminate in a finite time.

For example, consider the problem of adding two integers and displaying the result:

1. Ask the user for the first integer.
2. Store the first integer in variable A.
3. Ask the user for the second integer.
4. Store the second integer in variable B.
5. Initialize variable C to zero.
6. Add the contents of variables A and B, store the result in variable C.
7. Display the contents of variable C.

End.

Notations:

Use "Read" or "Input" for input operations.

Use "Print" or "Display" for output operations.

Use "=" for assignment.

Comments are written within square brackets to explain steps.

Sequential steps are separated by semicolons.

Use "If-Then" or "If-Then:Else" for conditional steps with relational operators.

Use "Repeat For" and "Repeat While" for iterative steps.

For example, finding the largest of three numbers:

Read a, b, c.

Set big to a.

If b > big, set big to b.

If c > big, set big to c.

Print big.

Stop.

1.3 PROGRAM ELEMENTARY 

Question: What is Data types In Programming C ?

Ans: In C programming, data types define the type of data that a variable can hold. They specify the size and format of values that can be stored in memory. in simple term what u want to store is a type of data like I have a Jar or Container and I want to store something on my jar so what I want to store like I want to store Water ? I want to store Lentils (Daal) basically what type of product I want to store is called Data type in Programming .

Data type is basically let you know how much bytes you want to hold on memory.

Question: Tell me data types in Programming C ?

Ans: 

1. Basic Data Types : Int, char,float,double                   
   int (Integer):
   Used to store integer values (whole numbers).
   Typically represented using 4 bytes (32 bits) of memory.
   Range: -2,147,483,648 to 2,147,483,647 for signed int.
   0 to 4,294,967,295 for unsigned int.
   Example:
   

   int age = 25;

1) In this Syntax int is a data type and age is just a variable name.

2) it will always start from small character int

        float (Floating Point):

        Used to store floating-point numbers (numbers with a fractional part).

        Typically represented using 4 bytes (32 bits) of memory.

        Range: Approximately ±3.4 x 10^-38 to ±3.4 x 10^38.

Example:

float weight = 65.5;

1) In this Syntax float is a data type and weight is just a variable name.

2) It will always start from small character float.

        double (Double Precision Floating Point):

        Used to store double-precision floating-point numbers (greater precision than float).

        Typically represented using 8 bytes (64 bits) of memory.

        Range: Approximately ±1.7 x 10^-308 to ±1.7 x 10^308.

        Example:

double pi = 3.14159265359;

1) In this Syntax double is a data type and pi is just a variable name.

2) It will always start from small character double.

3) we dont need to explain compiler that I want to store double.

        char (Character):

        Used to store single characters (e.g., letters, digits, symbols).

        Typically represented using 1 byte (8 bits) of memory.

        Range: -128 to 127 for signed char.

        0 to 255 for unsigned char.

        Example:

char grade = 'A';

1) In this Syntax char is a data type and grade is just a variable name.

2) It will always start from char.

3) we need to use single quoted sign to store char.

       2. Derived Data Types: Jinhe banane ke liye hame basic data types ki jarurt pdhti hai derived data types hote hai . 

Question: What is specifier in Data type of programming C ?

                                    or

Question: Explain Specifier for print data type or which type of data we want to print and scan.

Ans: In C programming, a specifier refers to a placeholder used in the printf() and scanf() functions to indicate the type and format of the data being printed or scanned. Specifiers start with the % character followed by a letter or sequence of letters that represent the data type being processed.

Question: What is Variable in Programming C ?

Ans: A variable in programming is like a container that holds values, and its value can change during program execution. The variable's name should be chosen meaningfully to reflect its purpose in the program.

Variable is the name of a memory location which stores some data

Question: Provide the Rules of Variables.

Ans: 

        a. Variables are case sensitive

        b. 1st character is alphabet or '_'

        c. no comma/blank space

        d. No other symbol other than '_'

Question: About Constant and Identifier .

Ans: Constants:

Containers to store values that remain unchanged during program execution.

Two types: Literal and Symbolic.

Literal Constant: Direct values like 10, without a name.

Types: Integer, Character, Floating Point.

Integer Constants: Decimal, Octal (start with 0), Hexadecimal (start with 0x).

Character Constants: Single characters in single quotes (e.g., 'a'), strings in double quotes (e.g., "a").

Identifiers:

Names for program elements (variables, functions, arrays).

Rules: Letters, digits, underscores; must start with a letter; case-sensitive; maximum length 32 characters.

Examples of valid identifiers: x, y12, sum_1, temperature, names, area, tax_rate, table.

Examples of invalid identifiers: x", order-no, total sum.

VARIABLE DECLARATIONS 

When you declare a variable in programming, you tell the compiler three things:

Variable Name: This is what you call the variable in your code.

Data Type: It defines what type of data the variable will hold (like numbers, characters, etc.).

Scope: This determines where in your code the variable can be accessed.

Variable Initialization:

After declaring a variable, you need to give it a value. This is called variable initialization.

You can do this in two ways:

Assignment Statement: This is where you directly assign a value to the variable using the assignment operator, like A = 153.

Read Statement: This involves using input functions like scanf() to read a value from the user and store it in the variable.

Initialization During Declaration:

You can combine variable declaration and initialization in a single statement, like int A = 153;. This is called initialization during declaration.

Grouping Variable Declarations:

It's a good practice to group together variables of the same type for easier management, like int j, k; float x, y, z;.

Examples of Variable Declarations:

int i = 0, j = 1;: Declaring and initializing integer variables i and j.

float basic_pay;: Declaring a floating-point variable basic_pay.

char a;: Declaring a character variable a.

double theta;: Declaring a double-precision floating-point variable theta.

Question:Explain the two methods for storing values in variables in programming.

Answer:

There are two main methods for storing values in variables:

Assignment Statement: This method involves directly assigning a value to the variable using the assignment operator (=). For example, A = 153; assigns the value 153 to the variable A.

Example:

int A;
A = 153; // Assigning the value 153 to variable A

// int A = 153; you can write like this also

// Displaying the value of variable A
printf("Value of A: %d\n", A);

Read Statement: This method involves using input functions like scanf() to read a value from the user or another source and store it in the variable. For instance, scanf("%d", &A); reads an integer value from the user and stores it in the variable A.

Example:

int A;

// Asking the user to input a value and storing it in variable A
printf("Enter a value for A: ");
scanf("%d", &A); // Reading an integer value from the user and storing it in variable A

// Displaying the value of variable A
printf("Value of A: %d\n", A);

Question: What are input and output processes?

Ans: 

Input Process:

                Definition: Input processes involve obtaining data from external sources and bringing it into the program for processing.

                Example: Reading Input from the User>> 

int num;

printf("Enter a number: "); // Prompting the user for input / message pass
scanf("%d", &num); // Reading an integer input from the user , and num is basically variable

where will store the integer and scanf is function to take input

printf("You entered: %d\n", num); // Displaying the input value

Output Process:

Definition: Output processes involve sending data produced by the program to external destinations such as the console, files, or other programs.

Example: Printing Output to the Console>>

int result = 42;

printf("The answer is: %d\n", result); // Printing output to the console

return 0;

Question: What are reserved words in C? Give examples

Ans: 

int: Specifies the integer data type.

float: Specifies the floating-point data type.

char: Specifies the character data type.

if: Used for conditional statements.

else: Used in conjunction with the "if" statement for alternative conditions.

for: Used for loop control.

while: Used for loop control.

do: Used in conjunction with the "while" loop for executing a block of code repeatedly.

switch: Used for multi-way decision-making.

case: Used within a "switch" statement to define different cases.

break: Used to exit from loops and switch statements.

continue: Used to skip the current iteration of a loop and proceed to the next iteration.

return: Used to exit a function and return a value.

void: Specifies that a function does not return any value.

sizeof: Used to determine the size of a data type or variable in bytes.

typedef: Used to create aliases for data types.

struct: Used to define a structure.

enum: Used to define enumeration types.

union: Used to define a union.

const: Specifies that a variable's value cannot be modified.

volatile: Specifies that a variable may be changed unexpectedly by external factors.

Question: What are variables? How are they declared in a C program?

Ans: Variables in C are named memory locations that hold values of a specific data type. They allow programmers to store and manipulate data within a program. When you declare a variable in C, you are essentially telling the compiler to set aside some memory for that variable, which can be used to store data during the execution of the program.

In Simple term set of data type and variable name .

Declaration of Variables in a C Program:

In C, variables are declared using the following syntax:

data_type variable_name;

data_type: Specifies the type of data that the variable will hold (e.g., int, float, char).

variable_name: Represents the name of the variable, which should follow the rules of identifier naming conventions in C.

Example:

int main()
{
    // Declaration of variables
    int age; // Declares an integer variable named "age"
    float height; // Declares a floating-point variable named "height"
    char grade; // Declares a character variable named "grade"

    // Assigning values to variables
    age = 25; // Assigns the value 25 to the variable "age"
    height = 5.8; // Assigns the value 5.8 to the variable "height"
    grade = 'A'; // Assigns the character 'A' to the variable "grade"

    // Displaying the values of variables
    printf("Age: %d\n", age);
    printf("Height: %.2f\n", height); // %.2f specifies two decimal places for floating-point output
    printf("Grade: %c\n", grade);

    return 0;
}

In this example:

>>We declared three variables: age of type int, height of type float, and grade of type char.

>>We assigned values to these variables using assignment statements.

>>We printed the values of these variables using printf statements.

>>This demonstrates the basic concept of variable declaration in a C program.

Question: What is C ?
C programming ek programming language hai jo ki computer programs likhne ke liye use hoti hai. Ye ek powerful, general-purpose programming language hai jiska upayog bahut se alag-alag applications develop karne ke liye kiya jata hai. C programming language ki shuruaat 1970s mein Bell Labs ke Dennis Ritchie dwara ki gayi thi, aur iske baad se hi ye ek popular programming language ban gayi hai.

C programming language ke kuch key features aur characteristics hai:

• Simplicity: C programming language ki syntax relatively simple hai, jiske wajah se ise samjhna aur likhna aasan hota hai.
• Portability: C programs ek platform se dusre platform par aasani se port kiya ja sakta hai. Iska matlab hai ki aap ek bar likha gaya C code alag-alag operating systems aur hardware par use kar sakte hain.
• Efficiency: C programming language ek low-level programming language hai, isliye aap directly hardware ke sath interact kar sakte hain, jo ki high performance applications ke liye mahatvapurn hai.
• Modularity: C mein code ko modules mein divide kiya ja sakta hai, jo ki code ko manage karne aur maintain karne mein madadgar hota hai.
• Rich Standard Library: C programming language ke sath aati hai ek rich standard library, jisme kai tarah ke functions aur utilities available hote hain, jo programming ko aasan banate hain.

C programming language ke use cases kai hain, jaise:

• System Programming: Operating systems aur embedded systems ke development mein C ka use hota hai.
• Application Development: C se aap desktop applications, mobile applications, aur games bhi develop kar sakte hain.
• Hardware Programming: C ko hardware programming ke liye use kiya ja sakta hai.
• Scientific Computing: Scientific research aur data analysis ke liye bhi C ka use hota hai.
• Web Development: C ka use server-side programming ke liye bhi hota hai, waise to web development ke liye dusre languages jyada popular hain, lekin C ka use networking aur protocols ke development mein hota hai.