C Programming Basics Quiz

C Programming Language Characteristics

C is a structured programming language, allowing code organization and modularity.
It is a procedural language, focusing on steps and algorithms.
C supports various data types, including integers, floats, characters, and arrays.
The language is portable, meaning it can be run on different platforms.
C offers a wide range of operators, including arithmetic, relational, logical, and bitwise.
C is a powerful and versatile language with a rich set of built-in functions and libraries.

Structure of a C Program

A C program typically consists of a set of functions, including a main function that serves as the program's entry point.
Functions are blocks of code that perform specific tasks.
Comments are used to explain code and are ignored by the compiler.
Preprocessing directives, starting with # (e.g., #include <stdio.h>) include headers and configure the compiler.
Variable declarations define the data types and names of variables used in the program.
Statements are instructions executed by the program in sequential order.
The return statement is used to return a value from a function.

Constants in C

Constants are fixed values that cannot be changed during program execution.
Integer constants: Whole numbers (e.g., 10, -5, 0).
Floating-point constants: Numbers with decimal points (e.g., 3.14, -2.5).
Character constants: Single characters enclosed in single quotes (e.g., 'A', '%').
String constants: Sequences of characters enclosed in double quotes (e.g., "Hello").

Tokens in C

Tokens are the basic building blocks of a C program, recognized by the compiler.
Example of each:
- Keywords: if, else, for, while
- Identifiers: name, age, sum
- Constants: 100, 3.14, 'a', "Hello"
- Operators: +, -, *, /, %, <, >, ==, !=
- Special Symbols: {, }, (, ), ;, #

Keywords and Identifiers

Keywords: Reserved words with special meaning in the C compiler.
Identifiers: User-defined names for variables, functions, arrays, etc.
Key Differences:
- Purpose: Keywords have predefined roles, while identifiers are user-created for specific entities.
- Case-sensitivity: Keywords are often case-insensitive, while identifiers may be case-sensitive depending on your compiler.

Data Types in C

Data types define the kind of data a variable can hold and the operations it can perform.
Basic Data Types:
- int: for integers (whole numbers)
- float: for floating-point numbers (numbers with decimal points)
- char: for single characters
- double: for larger floating-point numbers with higher precision
Derived Data Types:
- Arrays: Collections of elements of the same data type.
- Structures: User-defined data types that group variables of different types.
- Unions: Memory spaces that can hold different data types at different times.
- Pointers: Variables that store memory addresses.

Naming Conventions for Variables

Start with a Letter or underscore: counter, _radius
Use Alphanumeric Characters: total_cost, score_1
Case-Sensitive: totalCost is different from totalcost
No Spaces or Special Characters: Use underscores instead of spaces (e.g., balance_due).
Descriptive Names: Choose names that clearly explain the variable's purpose.

Program Examples

Ramesh's Gross Salary:

#include <stdio.h>

int main() {
    float basicSalary, dearnessAllowance, houseRentAllowance, grossSalary;

    printf("Enter Ramesh's basic salary: ");
    scanf("%f", &basicSalary);

    dearnessAllowance = 0.40 * basicSalary;
    houseRentAllowance = 0.20 * basicSalary;
    grossSalary = basicSalary + dearnessAllowance + houseRentAllowance;

    printf("Ramesh's gross salary is: %.2f\n", grossSalary);

    return 0;
}

Distance Conversion:

#include <stdio.h>

int main() {
    int distanceKm, distanceMeters, distanceCentimeters, distanceInches, distanceFeet;

    printf("Enter the distance between two cities in kilometers: ");
    scanf("%d", &distanceKm);

    distanceMeters = distanceKm * 1000;
    distanceCentimeters = distanceMeters * 100;
    distanceInches = distanceCentimeters / 2.54 ;
    distanceFeet = distanceInches / 12;

    printf("Distance in meters: %d\n", distanceMeters);
    printf("Distance in centimeters: %d\n", distanceCentimeters);
    printf("Distance in inches: %d\n", distanceInches);
    printf("Distance in feet: %d\n", distanceFeet);

    return 0;
}

Student Marks and Percentage:

#include <stdio.h>

int main() {
    int subject1, subject2, subject3, subject4, subject5, totalMarks, percentage;

    printf("Enter marks for subject 1: ");
    scanf("%d", &subject1);

    printf("Enter marks for subject 2: ");
    scanf("%d", &subject2);

    printf("Enter marks for subject 3: ");
    scanf("%d", &subject3);

    printf("Enter marks for subject 4: ");
    scanf("%d", &subject4);

    printf("Enter marks for subject 5: ");
    scanf("%d", &subject5);

    totalMarks = subject1 + subject2 + subject3 + subject4 + subject5;
    percentage = (totalMarks * 100) / 500;

    printf("Total Marks: %d\n", totalMarks);
    printf("Percentage: %d%%\n", percentage);

    return 0;
}

Fahrenheit to Centigrade Conversion:

#include <stdio.h>

int main() {
    float fahrenheit, centigrade;

    printf("Enter temperature in Fahrenheit: ");
    scanf("%f", &fahrenheit);

    centigrade = (fahrenheit - 32) * 5 / 9;

    printf("Temperature in Centigrade: %.2f\n", centigrade);

    return 0;
}

Rectangle and Circle Calculations:

#include <stdio.h>

int main() {
    float length, breadth, radius, rectangleArea, rectanglePerimeter, circleArea, circleCircumference;

    printf("Enter length of the rectangle: ");
    scanf("%f", &length);

    printf("Enter breadth of the rectangle: ");
    scanf("%f", &breadth);

    printf("Enter radius of the circle: ");
    scanf("%f", &radius);

    rectangleArea = length * breadth;
    rectanglePerimeter = 2 * (length + breadth);
    circleArea = 3.14159 * radius * radius;
    circleCircumference = 2 * 3.14159 * radius;

    printf("Rectangle Area: %.2f\n", rectangleArea);
    printf("Rectangle Perimeter: %.2f\n", rectanglePerimeter);
    printf("Circle Area: %.2f\n", circleArea);
    printf("Circle Circumference: %.2f\n", circleCircumference);

    return 0;
}

Swapping Two Numbers:

#include <stdio.h>

int main() {
    int c, d, temp;

    printf("Enter the value of C: ");
    scanf("%d", &c);

    printf("Enter the value of D: ");
    scanf("%d", &d);

    printf("Before swapping: C = %d, D = %d\n", c, d);

    temp = c;
    c = d;
    d = temp;

    printf("After swapping: C = %d, D = %d\n", c, d);

    return 0;
}

Branching and Looping in C

Branching: Used to alter the program's execution flow based on conditions.
- if statement: Executes a block of code if a condition is true.
- else statement: Executes a different block of code if the if condition is false.
- if-else if-else chain: Allows for multiple conditions to be evaluated.
Looping: Repeats a block of code multiple times until a certain condition is met.
- for loop: Executes a block of code a specific number of times.
- while loop: Executes a block of code as long as a condition remains true.
- do-while loop: Executes a block of code at least once, then checks a condition to continue looping.
Switch Statement: Evaluates an expression against a set of constant integer values, and executes the corresponding code block.
Goto Statement: Unconditionally jumps to a labeled statement within the same function, often avoided due to potential code complexity.
Comma Operator: Evaluates multiple expressions, with the last expression's value being returned. Used to combine statements that may be executed independently.

Operator Precedence in Expression Evaluation:

Operators have different priorities when evaluating expressions.
The order of operations is used to determine which operations are performed first:
- Parentheses: Expressions inside parentheses are evaluated first.
- Unary operators: Operators acting on single operands (e.g., !, -) are evaluated next.
- Multiplicative operators: *, /, %
- Additive operators: +, -
- Relational operators: ==, !=, <, >, <=, >=
- Logical operators: &&, ||
- Assignment operator: =

Prime Number Algorithm, Flowchart, and Code

Algorithm:
- Input an integer.
- If the number is less than 2, it's not a prime number.
- Iterate from 2 to the square root of the number.
- Check if the number is divisible by any of these values.
- If divisible, it's not a prime number; otherwise, it is.
Flowchart: (To be visually drawn but can't be included here - would visually show the steps described in the algorithm).
C Code:

#include <stdio.h>
#include <math.h>

int main() {
    int number, i, isPrime = 1; 

    printf("Enter a positive integer: ");
    scanf("%d", &number);

    if (number <= 1) {
        isPrime = 0; 
    } else {
        for (i = 2; i <= sqrt(number); i++) {
            if (number % i == 0) {
                isPrime = 0; 
                break; 
            }
        }
    }

    if (isPrime) {
        printf("%d is a prime number.\n", number);
    } else {
        printf("%d is not a prime number.\n", number);
    }

    return 0;
}

Continue Statement

The continue statement is used to skip the current iteration of a loop without terminating the loop entirely.
It jumps to the next iteration of the loop.

Switch Statement in C

Syntax:

switch (expression) {
    case constant_value1: 
        // Code to be executed if expression matches constant_value1
        break;
    case constant_value2:
        // Code to be executed if expression matches constant_value2
        break;
    // ... more cases
    default:
        // Code to be executed if no case matches
}

Example:

#include <stdio.h>

int main() {
    int day;

    printf("Enter a day of the week (1-7): ");
    scanf("%d", &day);

    switch (day) {
        case 1:
            printf("Monday\n");
            break;
        case 2:
            printf("Tuesday\n");
            break;
        case 3:
            printf("Wednesday\n");
            break;
        case 4:
            printf("Thursday\n");
            break;
        case 5:
            printf("Friday\n");
            break;
        case 6:
            printf("Saturday\n");
            break;
        case 7:
            printf("Sunday\n");
            break;
        default:
            printf("Invalid day number.\n");
    }

    return 0;
}

Loops and Their Types

Loops are used to repeat blocks of code as long as a certain condition is met.
For Loop: Repeats a block of code a specific number of times. It consists of three parts:
- Initialization: Executes once before the loop starts (e.g., setting a loop counter).
- Condition: Checked before each iteration. If true, the loop body executes; if false, the loop terminates.
- Increment/Decrement: Executed after each iteration (e.g., updating the loop counter).
While Loop: Keeps executing a block of code as long as a specified condition remains true. The condition is checked at the beginning of each iteration.
Do-While Loop: Similar to a while loop, but the condition is checked at the end of each iteration. This ensures the loop body executes at least once.

Conditional Statements in C

Conditional statements allow the program to make decisions based on conditions.
If Statement: Executes a block of code if a specified condition is true.
- Syntax:
```
if (condition) {
    // Code to be executedif condition is true
}
```

Else Statement: Executes a block of code if the if statement's condition is false.

Syntax:

if (condition) {
    // Code to be executed if condition is true
} else {
    // Code to be executed if condition is false
}

Else If Statement: Provides alternative conditions to be checked if previous if or else if conditions are false.

Syntax:

if (condition1) {
    // Code for condition1
} else if (condition2) {
    // Code for condition2
} else if (condition3) {
    // Code for condition3
} else {
    // Code for no matching condition
}

Factorial Calculation using Recursion

Recursion: A function calling itself within its own definition.
Factorial: The product of all positive integers less than or equal to a given number.
- Factorial of 5 (denoted as 5!) is 5 * 4 * 3 * 2 * 1 = 120.
C Code:

#include <stdio.h>

int factorial(int n);

int main() {
    int number, result;

    printf("Enter a non-negative integer: ");
    scanf("%d", &number);

    if (number < 0) {
        printf("Factorial is not defined for negative numbers.\n");
    } else {
        result = factorial(number);
        printf("Factorial of %d is %d\n", number, result);
    }

    return 0;
}

int factorial(int n) {
    if (n == 0) {
        return 1;  // Base case for recursion
    } else {
        return n * factorial(n - 1);  // Recursive step
    }
}

Arrays in C

Array: A collection of elements of the same data type, stored in contiguous memory locations.
Initialization:
- Direct initialization: Provide values directly during declaration (e.g., int numbers[5] = {1, 2, 3, 4, 5};)
- Partial initialization: Provide some values, others are assigned to 0 (e.g., int ages[10] = {20, 25, 30};) The remaining elements get 0.
- Indirect initialization: Assign values to elements individually after declaration (e.g., numbers[0] = 10; numbers[1] = 20;).

String Handling Functions in C

String: A sequence of characters terminated by a null character (\0).
Functions: (Five examples along with descriptions):
- strcpy(destination, source): Copies a string from source to destination.
- strcat(destination, source): Concatenates (joins) two strings.
- strlen(string): Returns the length of a string (excluding the null terminator).
- strcmp(string1, string2): Compares two strings lexicographically and returns an integer:
  - A negative value if string1 is alphabetically smaller than string2.
  - Zero if string1 and string2 are equal.
  - A positive value if string1 is alphabetically larger than string2.
- strchr(string, character): Finds the first occurrence of a specified character in a string and returns a pointer to that character.