Ask Programiz - Human Support for Coding Beginners

Hello Ramyasri.

An exception is not raised automatically for every error.
A catch block runs only if something is thrown.

Case 1: When you don’t need throw

Some C++ operations already know how to handle failure.
Memory allocation with new is one of them.

If new fails:

• C++ automatically throws an exception

• Control jumps directly to catch

• You don’t need to write throw yourself

So it feels like “magic”, but it’s actually built-in behavior.

Case 2: When you do need throw

In normal program logic (conditions, calculations, validations) and the current task in the lesson is calculation:

• C++ does not assume anything is an error

• Even if something is “wrong” by your logic, C++ keeps running

• No exception exists unless you explicitly create one

So unless you write throw, there is:

• No exception

• Nothing for catch to catch

• No error message

I hope I was able to explain it clearly. If you still have any confusion, please feel free to message me again and I’ll be happy to explain it in more detail.

Thank you for your question. keep up the great work in your learning journey! I look forward to hearing more questions from you.

Yes. A catch block only runs if something is thrown inside the try block.

In your example, throw 0; is what triggers the exception. When denominator == 0, the program throws 0, skips the remaining lines in the try block, and jumps straight to:

catch (int num) { ... }

If the denominator isn’t 0, nothing gets thrown, so the catch block is skipped and the program continues normally.

Feel free to reach out if you have any more queries.

Great question — let’s break it down clearly.

Operator precedence decides which operation is performed first in an expression. For example, multiplication and division have higher priority than addition and subtraction. So in this expression:

9 / 3 + 8 * 4 - 2

C++ first evaluates 9 / 3 and 8 * 4, then performs the addition and subtraction.

Associativity decides the direction in which operators are evaluated when they have the same priority. In C++, most arithmetic operators are evaluated from left to right. So in:

3 + 32 - 2

the addition is done before the subtraction.

To make expressions easier to read and control, you can use parentheses, like this:

(9 / 3) + (8 * 4) - 2

This clearly shows which parts are calculated first.

Hello Jay, really nice question.

An int didn’t become 4 bytes by magic — it’s mostly about how modern computers are built. Today’s systems are designed around 32-bit or 64-bit architectures, and a 4-byte (32-bit) integer lines up nicely with how the CPU reads and processes data.

Here’s the idea in simple terms:

1. Efficiency
   A 32-bit value fits naturally into the CPU’s data pathway, so the processor can read, write, and do math on it quickly.

2. Standard practice
   Over time, most platforms settled on 4 bytes for int because it balances speed and memory use. It became the “common size” on modern systems.

3. Range of values
   With 4 bytes, you can represent over four billion different values, which is enough for most everyday programming tasks.

If you run:

cout << sizeof(int);

and see 4, that’s your system telling you the natural size it uses.

If you have further questions, I'm here to help.

Hello Akmaral, really nice question.

When you write a countdown loop, you need a condition that tells Python exactly when to stop. Using i > 0 does that perfectly. As long as i is still greater than zero, the loop keeps running. The moment i hits zero, the condition becomes false, and the loop stops.

So if you start at 5 and subtract 1 each time:

i = 5
while i > 0:
    print(i)
    i = i - 1

you’ll get:

5
4
3
2
1

The loop ends right before it would go into negative numbers. It’s simply a clean and safe stopping point.

If you have further questions, I'm here to help.

Hello An, really nice question.

Yes, in C++ you can assign a default value to a function parameter, just like this:

void find_square(int number = 12) {
    int result = number * number;
    cout << "Square of " << number << " is " << result << endl;
}

Here’s what that means:

• If you call the function without an argument:

  find_square();    // uses number = 12
  

• If you call it with an argument:

  find_square(5);   // uses number = 5
  

So C++ will use the value you pass in if you provide one, and if you don’t, it falls back to the default value you wrote in the function definition.

Just remember:

• This works in C++, not in plain C.

• Default values are usually written in the function declaration (or definition), not repeated in multiple places.

If you have further questions, I'm here to help.

Hi Ian,

continue does not skip the loop condition. It only skips the rest of the code in the loop body for that one round, then the loop checks the condition again and moves to the next iteration.

Example:

for i in range(1, 6):
    if i == 3:
        continue
    print(i)  # prints 1, 2, 4, 5

If you have more questions, I am here to help.

Hello Ian, really nice question.

In C and C++, a while loop keeps running as long as its condition is true.
The key detail is: in C/C++, any non-zero value is treated as true, and 0 is treated as false.

So when you write:

while (1) {
    // loop body
}

the condition 1 is always true. There’s nothing inside the parentheses that can change over time – it’s just the constant value 1. That means the loop is set up to run forever, unless you manually stop it using something like break, return, or exiting the program.

In your example:

while (1) {
    cin >> number;

    if (number <= 0) {
        break;              // this is what actually stops the loop
    } else {
        total = total + number;
    }
}

What’s happening is:

1. while (1) creates an infinite loop.

2. Inside the loop, you read a number.

3. If the number is 0 or negative, you hit break, and that’s what exits the loop.

4. Otherwise, you keep adding to total and go around again.

So the idea is:

• while (1) = “keep looping until I decide to stop using break.”

• The real stop condition is written inside the loop, not in the while parentheses.

In modern C++, you’ll also see people write while (true) instead of while (1). They mean the same thing in this context, it’s just a bit more readable.

If you have further questions, I'm here to help.

Hello Ian, really nice question.

In C++, = and == look almost the same, but they do completely different things.

• = is the assignment operator
  It’s used to give a value to a variable.

  int x;
  x = 3;    // x gets the value 3
  

• == is the equality operator
  It’s used to compare two values and check if they are the same.

  if (x == 3) {
      // this runs only if x is equal to 3
  }
  

So in an if statement:

if (i == 3) {
    // checks: is i equal to 3?
}

you’re asking a question: “Is i equal to 3?”
The result is either true or false.

If you accidentally write:

if (i = 3) {
    // this is NOT a comparison
}

you are assigning 3 to i. The assignment itself evaluates to 3, which is treated as true in C++, so the if condition will always be true. That’s almost never what you want and can cause very confusing bugs.

So the short rule is:

• use = to set a value

• use == to check a value

If you have further questions, I'm here to help.

Hi Archana,

We use increment (++) and decrement (--) operators in C++ to quickly increase or decrease a variable's value by 1. They're mainly used for:

1. Simpler code
   Instead of writing i = i + 1, you can just write i++. It’s shorter and easier to read.

2. Looping
   These operators are commonly used in loops. For example:

   for (int i = 0; i < 5; i++) {
       cout << i << " ";
   }
   

   This loop prints: 0 1 2 3 4

3. Prefix vs Postfix

   • ++i (prefix) increases the value before it’s used

   • i++ (postfix) uses the value first, then increases it

   Example:

   int i = 5;
   cout << ++i; // Outputs 6  
   cout << i++; // Outputs 6, then i becomes 7
   

Both forms are useful depending on when you want the increment or decrement to happen.

If you have more questions, I’m here to help.