QUESTION DESCRIPTION 


Raju's maths teacher gave him a task of identifying the number name.

If the number is greater than 0 then he should utter to the teacher as "I am waiting".

If the number is less than 0 then he should utter the word as "I am not waiting".

If the number is "0" the he should utter the word as "Sorry" Help him by completing his task.

Refer Sample Test Cases.

Programming Language need to be used:C++

Solution: 

 #include <iostream>
using namespace std;
int main() {
int a;
  cin>>a;
  if(a<0)
  {
  cout<<"I am not waiting";
  }
  if(a>0)
  {
  cout<<"I am waiting";
  }
  if(a==0)
  {
  cout<<"Sorry";
  }
  return 0;

}

Task: Identifying Number Name Based on Its Value

Raju's task is a straightforward programming problem where he needs to respond with a specific message depending on whether the number is positive, negative, or zero. This problem allows us to delve into basic conditional logic in programming, using if-else statements, which are fundamental building blocks in most programming languages.

In this article, we will explain the task step-by-step, breaking down how the provided solution works, what the logic behind each condition is, and how the program correctly identifies the number's value and responds appropriately. Additionally, we'll explore sample test cases and explain how this problem can be extended to other real-world applications.

Problem Description

The goal of this problem is to:

  1. Read an integer input from the user.
  2. Print a message based on the value of the integer:
    • Print "I am waiting" if the number is positive (greater than 0).
    • Print "I am not waiting" if the number is negative (less than 0).
    • Print "Sorry" if the number is exactly 0.

This simple task uses basic conditional statements to evaluate the input and determine the appropriate output.

How the Code Works

Let’s break down the components of the solution:

1. Reading Input:

The first step of the task is to read an integer value from the user. In C++ (or most other programming languages), this can be done using standard input functions. Here is how it works in C++:


cin >> a;
  • The cin command reads the input from the user.
  • The input value is stored in the variable a, which will be an integer. This value will be used in the following steps to determine the output.

2. Conditional Checks:

Once the program has the input stored in the variable a, it moves to the next part of the task: determining whether the number is positive, negative, or zero.

The program uses a series of conditional checks to evaluate the value of a. Here’s how the logic is structured:

Checking if the number is negative:


if (a < 0)
{
    cout << "I am not waiting" << endl;
}
  • This line checks whether the value of a is less than 0.
  • If a is indeed less than 0, it indicates that the number is negative.
  • The program will print the message "I am not waiting" because the number is negative.

Checking if the number is positive:


else if (a > 0)
{
    cout << "I am waiting" << endl;
}
  • If the number is not negative (i.e., the condition a < 0 is false), the program proceeds to check whether the number is greater than 0.
  • If a is greater than 0, the program will print "I am waiting", indicating that the number is positive.

Checking if the number is zero:


else
{
    cout << "Sorry" << endl;
}
  • If both the previous conditions (i.e., a < 0 and a > 0) are false, the only remaining possibility is that a equals 0.
  • In this case, the program will print "Sorry", as this is the specific message designated for when the number is exactly zero.

3. Program Termination:

The final part of the program is:


return 0;
  • This line signals the end of the program. In C++, the return 0 statement indicates that the program has finished executing successfully without errors.
  • After printing the appropriate message based on the input, the program terminates.

Complete Code:

Here’s the complete code:


#include <iostream>
using namespace std;

int main()
{
    int a;
    cin >> a;

    if (a < 0)
    {
        cout << "I am not waiting" << endl;
    }
    else if (a > 0)
    {
        cout << "I am waiting" << endl;
    }
    else
    {
        cout << "Sorry" << endl;
    }

    return 0;
}

How the Code Works:

  1. Input Handling: The program asks for input and reads an integer a.
  2. Conditional Logic: It uses if, else if, and else to determine if the number is positive, negative, or zero, printing different messages accordingly.
  3. Termination: The program concludes by returning 0, indicating successful completion.

Example Test Cases

Now, let’s explore some sample test cases to understand how this code performs.

Test Case 1: Positive Number

  • Input: 5
  • Process:
    • The program reads the value 5 and checks the condition a < 0. This condition is false.
    • Then, it checks a > 0, which is true because 5 is greater than 0.
    • As a result, the program prints "I am waiting".
  • Output: "I am waiting"

Test Case 2: Negative Number

  • Input: -3
  • Process:
    • The program reads the value -3 and checks the condition a < 0, which is true because -3 is less than 0.
    • Therefore, the program prints "I am not waiting".
  • Output: "I am not waiting"

Test Case 3: Zero

  • Input: 0
  • Process:
    • The program reads the value 0 and checks a < 0, which is false.
    • It then checks a > 0, which is also false.
    • Since both conditions are false, the program moves to the else statement and prints "Sorry".
  • Output: "Sorry"

Key Concepts Behind the Solution

The solution to this problem uses basic programming concepts that are foundational in almost every programming language. Let's explore these concepts in more detail:

1. Conditional Statements (if-else)

Conditional statements are used to make decisions in a program based on specific conditions. The syntax of if-else is:


if (condition) {
    // code to be executed if condition is true
} else if (another condition) {
    // code to be executed if the first condition is false and this condition is true
} else {
    // code to be executed if all other conditions are false
}

In Raju's case, the program has three possible conditions to check:

  • If the number is negative (a < 0).
  • If the number is positive (a > 0).
  • If the number is zero (handled by the else block).

This simple structure allows the program to execute different code based on the value of the input.

2. Input Handling (cin)

In C++, the cin function is used to take user input. In this task, cin >> a; captures the input provided by the user and stores it in the variable a. This value is then used for comparison in the conditional statements.

3. Output Handling (cout)

The cout function in C++ is used to display output. In this case, depending on the value of a, different messages are printed:

  • "I am waiting" for positive numbers.
  • "I am not waiting" for negative numbers.
  • "Sorry" for zero.

4. Program Flow

The program executes line by line, following a linear flow:

  • First, the program reads the input.
  • Then, it evaluates the input using conditional checks.
  • Based on the result of the evaluation, it prints the corresponding message and terminates.

Extension: Handling Edge Cases and Additional Logic

This problem, though simple, can be extended or modified for more complex scenarios. Let’s explore some additional cases or features that can be added to this task:

1. Handling Non-Integer Inputs

Currently, the program assumes that the input is an integer. If non-integer inputs (e.g., decimals or characters) are provided, the program could fail. We can add input validation to handle such cases.

2. Handling Large Inputs

The program works for typical integer inputs, but what if a user enters extremely large or small numbers? Depending on the programming environment, this could cause overflow or underflow errors. We could modify the program to handle larger data types like long long or use error handling techniques.

3. Providing Feedback for Invalid Input

If the input is not a valid integer, we can add a check to inform the user and prompt them to enter a valid number.

For instance:


if (cin.fail()) {
    cout << "Invalid input. Please enter an integer." << endl;
} else {
    // Proceed with the number checks
}

This ensures the program can handle a wider range of input cases without crashing.

4. Multiple Inputs or Looping

If Raju’s task required handling multiple inputs (e.g., checking numbers in a loop), we could add a loop that continues to read numbers until the user decides to stop.

Here’s an example of how we could add a loop to check multiple numbers:

while (true) {
    int a;
    cout << "Enter a number (or type -999 to quit): ";
    cin >> a;
    
    if (a == -999) {
        break; // Exit the loop

when the user inputs -999.

    }

    if (a < 0)
    {
        cout << "I am not waiting" << endl;
    }
    else if (a > 0)
    {
        cout << "I am waiting" << endl;
    }
    else
    {
        cout << "Sorry" << endl;
    }
}

This modified version of the program will keep prompting the user for input until they enter -999. This kind of loop is useful when you want to process multiple numbers in one go without having to restart the program each time.
5. Providing Detailed Responses Based on Ranges
We can also enhance the feedback based on the magnitude of the number. For example, instead of only saying "I am waiting" or "I am not waiting," we could add more descriptive responses for specific ranges of numbers:
  • Numbers greater than 100 could produce the message "I am very much waiting!"
  • Numbers less than -100 could produce the message "I am definitely not waiting!"
Here’s an example:

if (a < -100)
{
    cout << "I am definitely not waiting" << endl;
}
else if (a < 0)
{
    cout << "I am not waiting" << endl;
}
else if (a > 100)
{
    cout << "I am very much waiting" << endl;
}
else if (a > 0)
{
    cout << "I am waiting" << endl;
}
else
{
    cout << "Sorry" << endl;
}

This makes the program more dynamic and provides varied output depending on the input’s magnitude.
6. Real-World Applications of Conditional Logic
This type of task, where output depends on the evaluation of input values, is commonly seen in real-world applications. Let’s discuss some areas where similar logic is applied:
1. Temperature Control Systems
Imagine a smart thermostat that adjusts based on the current room temperature. The thermostat uses conditional logic similar to our example. It might display different messages or take action depending on the temperature range, for example:
  • If the temperature is too low, it may turn on the heater and display “Heating”.
  • If the temperature is too high, it may turn on the air conditioner and display “Cooling”.
  • If the temperature is just right, it may do nothing and display “Comfortable”.
2. Traffic Light Systems
Traffic lights use conditional logic to control the flow of traffic. Sensors may detect vehicles and then change the light accordingly:
  • If no cars are detected, the system might keep the light green for one direction and red for another.
  • If a car approaches, the system might switch the light to yellow and then red to stop cars in one direction while allowing traffic from another.
3. Online Forms and User Input Validation
When you fill out an online form, the website often checks if the input is valid. For example, if you enter a number where a string is expected, the system might display an error message asking for a correction. Conditional logic is used here to validate inputs:
  • If an email address is incorrectly formatted, the form might display “Invalid email address.”
  • If a required field is left blank, the form might display “Please fill in this field.”
In these examples, conditional statements help make decisions based on the input or data received, just like how Raju’s task involved printing a message depending on the value of a number.
7. Conclusion
In this task, Raju’s job was to identify a number based on its value—whether it was positive, negative, or zero—and respond with a specific message. The program used basic input handling (cin), conditional logic (if-else), and output commands (cout) to achieve this. The solution effectively handles different cases and provides the appropriate response based on the number entered.
By expanding the program, we can handle multiple inputs, provide more detailed feedback, and even validate input to make the program more robust. These principles of conditional logic are foundational in programming and have broad applications in many real-world systems, from temperature control to web forms.
Raju’s task exemplifies how even simple logic can be powerful, and by understanding this basic concept, we can apply it to much more complex scenarios and challenges.