Introduction to Programming in C++

Introduction to Programming

Start with the basics, use pseudocode and flowcharts, practice, focus on problem-solving techniques, keep it simple, test and debug, learn from others, and stay patient and persistent.

Welcome to the world of programming! Are you ready to start an exciting journey into the world of programming? Don’t worry if it sounds a bit scary - we’re here to make it super easy and fun for you!

What’s This Guide All About?

This guide is like your friendly neighbor who’s really good at puzzles. We’re going to help you learn how to solve computer puzzles (that’s what programming is!) using a language called C++. But we’re not just going to teach you random stuff - we’re focusing on something really cool called Data Structures and Algorithms. Don’t worry if those words sound big right now - by the end of this guide, you’ll be using them like a pro!

1. Introduction to Programming

Imagine you’re teaching your pet dog a new trick. You give it step-by-step instructions: “Sit”, “Roll over”, “Stand up”. That’s exactly what programming is! You’re giving your computer step-by-step instructions to do something cool.

C++ is just one of the many languages we can use to give these instructions. It’s like learning French or Spanish, but for talking to computers!

2. How to Approach Problems

When you’re faced with a tricky problem, it’s easy to feel lost. But don’t worry! We’ve got a super simple method to tackle any problem. It’s like a recipe for problem-solving:

• Step 1: Understand the problem Just like reading a recipe before cooking, read the problem carefully. Make sure you know what it’s asking.
• Step 2: Enter appropriate input value for the problem This is like gathering all your ingredients before cooking. What information do you need to solve this problem?
• Step 3: Create logics/algorithms to solve the problem Now, think about the steps to solve the problem. It’s like planning how you’ll mix your ingredients and in what order.
• Step 4: Dry run the logics/algorithms for different test cases Before you start coding, test your plan in your head or on paper. It’s like tasting your dish before serving it to make sure it’s good!
• Step 5: Write code for the problem Finally, write your solution in C++. This is like actually cooking your meal after all the planning.

3. What is Pseudocode?

Pseudocode is like a rough draft of your program. It’s written in simple English (or any language you’re comfortable with) and describes what your program will do, step by step. It’s not actual code, but it helps you organize your thoughts before you start coding.

For example, pseudocode for making a sandwich might look like this:

1. Get two slices of bread
2. Spread butter on one side of each slice
3. Put a slice of cheese on one piece of bread
4. Put the other slice of bread on top, buttered side down
5. Put the sandwich in a pan
6. Cook until golden brown on both sides

4. What is a Flowchart?

A flowchart is like a map of your program. It uses different shapes and arrows to show the steps your program will take. It’s a visual way to represent your algorithm.

Components of a Flowchart:

• Start/Stop: This is an oval shape that shows where your program begins and ends.
• Process: This is a rectangle that represents a step in your program.
• Input/Output: This is a parallelogram that shows when your program is getting information or showing results.
• Decision: This is a diamond shape that represents a yes/no question in your program.
• Arrow: These show the order of the steps in your program.
• On-Page Connector: This is a small circle that connects different parts of your flowchart on the same page.
• Off-Page Connector: This is like the on-page connector, but it connects parts of your flowchart that are on different pages.

How to Draw a Flowchart for a Problem with Pseudocode

• Step 1: Write pseudocode Start by writing out your algorithm in simple language.
• Step 2: Draw flowchart Turn each step of your pseudocode into a flowchart shape.
• Step 3: Write code Use your flowchart as a guide to write your actual C++ code.

Practice with Flowchart, Pseudocode, and Code for Different Problems

Let’s practice with some simple problems. We’ll show you the pseudocode, flowchart, and C++ code for each one.

Problem 1: Print sum of A and B

Pseudocode:

1. Start
2. Input number A
3. Input number B
4. Calculate Sum = A + B
5. Print Sum
6. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int A, B, Sum;
    cout << "Enter number A: ";
    cin >> A;
    cout << "Enter number B: ";
    cin >> B;
    Sum = A + B;
    cout << "Sum is: " << Sum;
    return 0;
}

Output:

Enter number A: 10
Enter number B: 20
Sum is: 30

Problem 2: Average of A, B, and C

Pseudocode:

1. Start
2. Input numbers A, B, and C
3. Calculate Average = (A + B + C) / 3
4. Print Average
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    float A, B, C, Average;
    cout << "Enter three numbers: ";
    cin >> A >> B >> C;
    Average = (A + B + C) / 3;
    cout << "Average is: " << Average;
    return 0;
}

Output:

Enter three numbers: 10 20 30
Average is: 20

Problem 3: Print twice of A

Pseudocode:

1. Start
2. Input number A
3. Calculate Double = A * 2
4. Print Double
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int A, Double;
    cout << "Enter a number: ";
    cin >> A;
    Double = A * 2;
    cout << "Twice of " << A << " is: " << Double;
    return 0;
}

Output:

Enter a number: 10
Twice of 10 is: 20

Problem 4: Find area of square

Pseudocode:

1. Start
2. Input side length of square
3. Calculate Area = side * side
4. Print Area
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    float side, area;
    cout << "Enter the side length of the square: ";
    cin >> side;
    area = side * side;
    cout << "Area of the square is: " << area;
    return 0;
}

Output:

Enter the side length of the square: 10
Area of the square is: 100

Problem 5: Calculate overall percentage from marks

Pseudocode:

1. Start
2. Input marks for 5 subjects
3. Calculate Total = sum of all marks
4. Calculate Percentage = (Total / 500) * 100
5. Print Percentage
6. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    float marks[5], total = 0, percentage;
    cout << "Enter marks for 5 subjects: ";
    for(int i = 0; i < 5; i++) {
        cin >> marks[i];
        total += marks[i];
    }
    percentage = (total / 500) * 100;
    cout << "Overall percentage: " << percentage << "%";
    return 0;
}

Output:

Enter marks for 5 subjects: 90 80 70 60 50
Overall percentage: 80.0%

Problem 6: Check if number is even or odd

Pseudocode:

1. Start
2. Input number
3. If (number % 2 == 0)
       Print "Even"
   Else
       Print "Odd"
4. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int number;
    cout << "Enter a number: ";
    cin >> number;
    if(number % 2 == 0)
        cout << number << " is Even";
    else
        cout << number << " is Odd";
    return 0;
}

Output:

Enter a number: 10
10 is Even

Problem 7: Check number is positive or negative or zero

Pseudocode:

1. Start
2. Input number
3. If (number > 0)
       Print "Positive"
   Else If (number < 0)
       Print "Negative"
   Else
       Print "Zero"
4. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int number;
    cout << "Enter a number: ";
    cin >> number;
    if(number > 0)
        cout << number << " is Positive";
    else if(number < 0)
        cout << number << " is Negative";
    else
        cout << "The number is Zero";
    return 0;
}

Output:

Enter a number: 10
10 is Positive

Problem 8: Create student and grade flowchart and pseudocode

Pseudocode:

1. Start
2. Input student name
3. Input marks for 3 subjects
4. Calculate average = (subject1 + subject2 + subject3) / 3
5. If (average >= 90)
       Grade = 'A'
   Else If (average >= 80)
       Grade = 'B'
   Else If (average >= 70)
       Grade = 'C'
   Else If (average >= 60)
       Grade = 'D'
   Else
       Grade = 'F'
6. Print student name, average, and grade
7. Stop

Flowchart:

C++ Code:

#include <iostream>
#include <string>
using namespace std;

int main() {
    string name;
    float subject1, subject2, subject3, average;
    char grade;

    cout << "Enter student name: ";
    getline(cin, name);
    cout << "Enter marks for 3 subjects: ";
    cin >> subject1 >> subject2 >> subject3;

    average = (subject1 + subject2 + subject3) / 3;

    if(average >= 90)
        grade = 'A';
    else if(average >= 80)
        grade = 'B';
    else if(average >= 70)
        grade = 'C';
    else if(average >= 60)
        grade = 'D';
    else
        grade = 'F';

    cout << "Student: " << name << endl;
    cout << "Average: " << average << endl;
    cout << "Grade: " << grade;

    return 0;
}

Output:

Enter student name: Manoj Kumar
Enter marks for 3 subjects: 80 90 70
Student: Manoj Kumar
Average: 80.0
Grade: B

Problem 9: Counting number from 1 to n

Pseudocode:

1. Start
2. Input n
3. Set counter = 1
4. While (counter <= n)
       Print counter
       Increment counter
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n, counter = 1;
    cout << "Enter a number: ";
    cin >> n;
    while(counter <= n) {
        cout << counter << " ";
        counter++;
    }
    return 0;
}

Output:

Enter a number: 10
1 2 3 4 5 6 7 8 9 10

Problem 10: Multiplying number from 1 to n

Pseudocode:

1. Start
2. Input n
3. Set result = 1
4. For i = 1 to n
       result = result * i
5. Print result
6. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n, result = 1;
    cout << "Enter a number: ";
    cin >> n;
    for(int i = 1; i <= n; i++) {
        result *= i;
    }
    cout << "Product of numbers from 1 to " << n << " is: " << result;
    return 0;
}

Output:

Enter a number: 5
Product of numbers from 1 to 5 is: 120

Problem 11: Print even numbers from 1 to n

Pseudocode:

1. Start
2. Input n
3. Set counter = 2
4. While (counter <= n)
       Print counter
       Increment counter by 2
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n, counter = 2;
    cout << "Enter a number: ";
    cin >> n;
    cout << "Even numbers from 1 to " << n << " are: ";
    while(counter <= n) {
        cout << counter << " ";
        counter += 2;
    }
    return 0;
}

Output:

Enter a number: 10
Even numbers from 1 to 10 are: 2 4 6 8 10

Problem 12: Multiplying two numbers A and B taking input from user

Pseudocode:

1. Start
2. Input number A
3. Input number B
4. Calculate Product = A * B
5. Print Product
6. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int A, B, Product;
    cout << "Enter number A: ";
    cin >> A;
    cout << "Enter number B: ";
    cin >> B;
    Product = A * B;
    cout << "Product of " << A << " and " << B << " is: " << Product;
    return 0;
}

Output:

Enter number A: 5
Enter number B: 10
Product of 5 and 10 is: 50

Problem 13: Find the perimeter of triangle

Pseudocode:

1. Start
2. Input side1, side2, side3
3. Calculate Perimeter = side1 + side2 + side3
4. Print Perimeter
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    float side1, side2, side3, perimeter;
    cout << "Enter the lengths of three sides of the triangle: ";
    cin >> side1 >> side2 >> side3;
    perimeter = side1 + side2 + side3;
    cout << "The perimeter of the triangle is: " << perimeter;
    return 0;
}

Output:

Enter the lengths of three sides of the triangle: 5 6 7
The perimeter of the triangle is: 20

Problem 14: Find the simple interest

Pseudocode:

1. Start
2. Input Principal (P), Rate (R), Time (T)
3. Calculate SimpleInterest = (P * R * T) / 100
4. Print SimpleInterest
5. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    float principal, rate, time, simpleInterest;
    cout << "Enter Principal amount: ";
    cin >> principal;
    cout << "Enter Rate of interest (per year): ";
    cin >> rate;
    cout << "Enter Time (in years): ";
    cin >> time;
    simpleInterest = (principal * rate * time) / 100;
    cout << "Simple Interest is: " << simpleInterest;
    return 0;
}

Output:

Enter Principal amount: 1000
Enter Rate of interest (per year): 10
Enter Time (in years): 2
Simple Interest is: 200

Problem 15: Find the compound interest

Pseudocode:

1. Start
2. Input Principal (P), Rate (R), Time (T), Number of times interest is compounded per year (n)
3. Calculate Amount = P * (1 + R/(100*n))^(n*T)
4. Calculate CompoundInterest = Amount - P
5. Print CompoundInterest
6. Stop

Flowchart:

C++ Code:

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    float principal, rate, time, n, amount, compoundInterest;
    cout << "Enter Principal amount: ";
    cin >> principal;
    cout << "Enter Rate of interest (per year): ";
    cin >> rate;
    cout << "Enter Time (in years): ";
    cin >> time;
    cout << "Enter number of times interest is compounded per year: ";
    cin >> n;
    amount = principal * pow((1 + rate/(100*n)), (n*time));
    compoundInterest = amount - principal;
    cout << "Compound Interest is: " << compoundInterest;
    return 0;
}

Output:

Enter Principal amount: 1000
Enter Rate of interest (per year): 10
Enter Time (in years): 2
Enter number of times interest is compounded per year: 2
Compound Interest is: 200

Problem 16: Print counting from n to 1

Pseudocode:

1. Start
2. Input n
3. While (n >= 1)
       Print n
       Decrement n
4. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "Enter a number: ";
    cin >> n;
    cout << "Counting from " << n << " to 1: ";
    while(n >= 1) {
        cout << n << " ";
        n--;
    }
    return 0;
}

Output:

Enter a number: 5
Counting from 5 to 1: 5 4 3 2 1

Problem 17: Find the factorial of a number

Pseudocode:

1. Start
2. Input n
3. Set factorial = 1
4. For i = 1 to n
       factorial = factorial * i
5. Print factorial
6. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n;
    unsigned long long factorial = 1;
    cout << "Enter a positive integer: ";
    cin >> n;
    if (n < 0)
        cout << "Error! Factorial of a negative number doesn't exist.";
    else {
        for(int i = 1; i <= n; ++i) {
            factorial *= i;
        }
        cout << "Factorial of " << n << " = " << factorial;
    }
    return 0;
}

Output:

Enter a positive integer: 5
Factorial of 5 = 120

Problem 18: Check if number is prime or not

Pseudocode:

1. Start
2. Input n
3. If n <= 1
       Print "Not Prime"
4. For i = 2 to sqrt(n)
       If n is divisible by i
           Print "Not Prime"
           Stop
5. Print "Prime"
6. Stop

Flowchart:

C++ Code:

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    int n;
    bool isPrime = true;
    cout << "Enter a positive integer: ";
    cin >> n;
    if (n <= 1) {
        isPrime = false;
    } else {
        for (int i = 2; i <= sqrt(n); ++i) {
            if (n % i == 0) {
                isPrime = false;
                break;
            }
        }
    }
    if (isPrime)
        cout << n << " is a prime number";
    else
        cout << n << " is not a prime number";
    return 0;
}

Output:

Enter a positive integer: 5
5 is a prime number

Problem 19: Check valid triangle or not

Pseudocode:

1. Start
2. Input side1, side2, side3
3. If (side1 + side2 > side3) AND (side2 + side3 > side1) AND (side3 + side1 > side2)
       Print "Valid Triangle"
   Else
       Print "Not a Valid Triangle"
4. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    float side1, side2, side3;
    cout << "Enter the lengths of three sides of the triangle: ";
    cin >> side1 >> side2 >> side3;
    if (side1 + side2 > side3 && side2 + side3 > side1 && side3 + side1 > side2)
        cout << "This is a valid triangle";
    else
        cout << "This is not a valid triangle";
    return 0;
}

Output:

Enter the lengths of three sides of the triangle: 3 4 5
This is a valid triangle

Problem 20: Print the maximum number from three numbers A, B, and C

Pseudocode:

1. Start
2. Input A, B, C
3. Set max = A
4. If B > max
       max = B
5. If C > max
       max = C
6. Print max
7. Stop

Flowchart:

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int A, B, C, max;
    cout << "Enter three numbers: ";
    cin >> A >> B >> C;
    max = A;
    if(B > max)
        max = B;
    if(C > max)
        max = C;
    cout << "The maximum number is: " << max;
    return 0;
}

Output:

Enter three numbers: 3 4 5
The maximum number is: 5

Conclusion

This guide covers the basics of programming in C++ with a focus on problem-solving techniques. It includes an introduction to programming, problem-solving approaches, pseudocode, flowcharts, and practical examples with code. The content is presented in an easy-to-understand manner, suitable for beginners in programming.

Happy coding!