Do you know what is exception handling in C++? If not, do not worry! CodingZap is here to explain this concept to you.
If I were to say it simply, exceptions are those scenarios that lead to some unexpected behavior of a program that may lead to the termination of the program abruptly. You must be wondering why do need to handle exceptions. Why is exception handling important?
While writing a code there may be some exceptions that happen to the code. That exception can be from the machine side or the programmer side. But an exception can happen. So programmers will try to handle those exceptions.
That is why some methods help programmers to escape such situations. As if a code is being caught by an exception it will stop working or running. So, that will hamper the practicality of the code.
But wait! Is there any method to overcome such scenarios? Yes, there are!
Summary of the Article:
- Exceptions are certain types of abnormalities that may occur during the execution of a program.
- They may lead to inefficiency in the program and may also terminate it abruptly with some errors.
- Exceptions in C++ can be classified into two categories – synchronous and asynchronous.
- It is important to handle exceptions and perform error handling so that our program does not behave abnormally.
What Are C++ Exceptions? Read Below
C++ Exceptions are those things that can happen to any length of the program. Suppose, a programmer is writing a piece of code. The programmer knows that at any point in time the program gets stopped. But why? At any point, the program can generate a particular random number for that code. An inappropriate random number can stop the execution.
Let’s take an example:
Suppose, the main goal of a program is to divide any particular number with any random number from 0 to 10. Now, at any point in time, the number is generated as zero. So, dividing by zero will always prompt an output. This is called an exception. This exception can happen at any time.
So, the C++ programmer knows such a scenario can happen. So, the programmer will use a particular method. That will help to overcome such errors. This method is called exception handling in C++.
Types Of C++ Exceptions? Know More
There are mainly two types of exceptions present in the world of programming. Not only C++ but also all types of Object-Oriented Programming (OOP) Languages have such exceptions. They are:
Synchronous Exception or Programmer-Made Exception:
These exceptions are made by a programmer. Or we can state it like, these exceptions can be thought of by a programmer while writing a code. Like, as division by zero. So, these types of exceptions can be easily removed. The maximum type of exceptions is from this category.
Asynchronous Exception or Machine-Made Exception:
These exceptions can’t be controlled or removed by programmers. These types of exceptions are closely associated with the machine itself. Due to memory failure disk interruption or due to keyboard interruption these types of exceptions can be found. However these types of exceptions are very rare to see.
What Is Exception Handling In C++? Read Below
There is only one method present for exception handling in C++. The method consists of three sub-methods. Each method represents a particular block that has its function. You can combine one or more blocks to perform C++ exception handling.
But before we move forward, let’s know those sub-methods and learn the exception handling in C++ syntax as we move further:
C++ Try Sub Method:
In this block, we have to write some piece of code. The part of the code that can prompt an exception will be thrown. For example, if you want to write a code for the division of numbers, the instructions for the same will come in this block.
General Syntax: try{//statement}
C++ Throw Sub Method:
This is a single-line statement. We have to write the piece of code which can create the exception. Throwing an exception in Java is a common practice for handling exceptional situations. The throwing method will move the section of code to the catch method.
General Syntax: throw statement;
C++ Catch Sub Method:
The catch method will receive the piece of code as an argument & provide a default output. Hence the program will not get terminated abnormally.
General Syntax: catch (argument) {//statement}
Do you wish to know how does exception handling work in C++? Let us explore further!
Let us see how to check exception handling in C++. We can divide the Try Catch method into two further methods also. They are:
- Try Catch C++ : Normal Method
- Try Catch C++: Catch All Method
Normal Method – C++ Try Catch Example:
In this method, we normally use the Try Catch block. The same syntax we use here. That is why it is often called as Normal Method.
Here, we have to take two user input values. In between them, the second one can be sometimes zero. As we are performing the division, division by zero can’t happen. That is why we here used normal Try Catch blocks.
If the second number is zero, then it will throw the exception to the Catch block. The Catch block will receive the second number as an argument & print a default statement.
If the second number is not zero, then it will simply do the division operation & provide the output.
Hence, this is the only simple method that helps us to do exception handling in C++.
Example:
#include <iostream>
using namespace std;
int main()
{
int a,b; // Declaring The Variables
// Taking Input From User For The First Number
cout << "Enter First Number: ";
cin >> a;
// Taking Input From User For The Second Number
cout << "Enter Second Number: ";
cin >> b;
// Implementing try Block
try
{
// Checking The Second Number Zero or Not
if (b == 0)
{
// If The Second Number Is Zero Throw Statement Will Work
throw b;
}
// If The Second Number Is Not Zero Then The Below Statement Will Work
else
{
cout << "Result Is: " << a/b; // Result Will Be Printed
}
}
// Catch Block Accepts The Second Value As Argument
catch (int b)
{
cout << "Division By Zero Not Allowed"; // Printting The Default Statement
}
return 0;
}
Did you face any difficulty understanding the code? Don’t worry, you can get help from reliable C++ programming homework experts and clear all your doubts.
Let’s look at the output of the above code. Hence, we come to know about exception handling in C++
Output:
Without Divided By Zero
Let us observe what happened in the above code. Since, our input numbers were 4 and 2 that gives us the answer 2, without any case/scenario for an exception, only the Try block was executed here.
With Divided By Zero
In this C++ program, we have a scenario, where we were dividing 5 by 0, that will not give us an integer or float answer. Divide by zero is not possible, therefore, the Try block throws this error/ exception that then enters the catch block and we print ‘Division By Zero Not Allowed’
Catch All Method – C++ Try Catch Example:
In this case, all types of exceptions can be able to accept the block. Here, we have declared one integer variable. We are throwing that as an exception. There are two types of catch blocks. One is for catching character-related exceptions & another for all types of exceptions.
The catch block for catching the character-related exception can’t able to receive the integer exception. So, in this case, the second catch block will receive that.
It doesn’t have any argument specification. That is why it can able to take any exceptions.
General Syntax: catch(…){//statement}
Example:
#include <iostream>
using namespace std;
int main(){
int x=10; // Declaring The Variable
// Implementing try Block
try {
throw x; // Throwing The Exception
}
// Catch Block To Accept The Exceptions Related to Characters
catch (char x) {
cout << "Caught In Normal Method";
}
// Catch Block To Accept All Type Of Exceptions
catch (...) {
cout << "Caught In Catch All Method";
}
return 0;
}
Let’s look at the output of the above code. Hence, we come to know about exception handling in C++.
Output:
In the above C++ program, we have two catch statements that return values as per the instructions in their blocks. We are using the catch block for accepting all values of x that have a character datatype when we use the throw keyword for it. Otherwise, the catch-all function will accept any other kind of value for x.
Now that we have learned exception handler operations, and we know how to implement them. Let us explore further into the topic and learn about exception classes in C++.
What are the C++ Standard Exception Classes?
The C++ programming language provides us with some standard exceptions that are defined under the <exception> header file. This list of exceptions can be used by C++ programmers in their C++ code for exception handling and to tackle some kind of runtime error.
Let us see the basic description of each exception in C++ in the table below!
Exception | Description |
std::exception | The parent class for all the other exception classes |
std::logic_error | For representation of errors in the programming logic |
std::runtime_error | For errors/exceptions that are detected during program execution |
std::invalid_argument | Represents errors due to invalid or incorrect arguments |
std::bad_alloc | Thrown by new, represents failure in memory allocation |
std::bad_typeid | Thrown by typeid, reports a null pointer |
std::overflow_error | For mathematical or arithmetic overflows |
std::underflow_error | For mathematical or arithmetic underflow |
std::range_error | For errors that occur during storage of values out of range |
std::length_error | For errors when a large std::string is created |
Best Practices for Exception Handling
So far, we have learned enough information about error handling and exception handling. Let us now see how you can make use of these to the fullest! Here are a few things you should keep in mind while using exceptions in C++.
- Use exceptions for runtime errors or anomalies only. You should not implement exception handling for the flow of control in a program.
- Using a specific catch exception rather than using catch all statements will give you more efficient result and enhance code readability as well.
- Keeping your catch blocks concise and aligned towards catching a specific kind of exception is the way to go!
- Providing meaningful error messages in your exception mechanism helps in showing effective ways to debug issues as well.
- Try to avoid resources leak from resources like memory, file handlers, or network when they are released during an exception.
- Try to use the C++ Standard Library Exceptions to promote consistency in your C++ code.
Real-World Use Cases of C++ Exception Handling
Now that we have a better idea about exception handling mechanisms in C++, let us see in which case/scenario we can use the implementation of exceptions in our project. Let’s know more!
- For I/O operations: We can implement the exceptional blocks when working with the file stream. There are cases, when unexpected behavior is seen because of various reasons like disk full, file not found, etc. Using exceptions for such cases, helps in seamless error handling.
- For Database operations: Query execution errors, connection errors, and other operations in the database may lead to errors, making your job complex. Exceptions can help in rollbacking transactions and keeping a log of error details for analysis and feedback. If you want to know about errors in programming languages like C, then you can check out the article “Errors in C“
- For API integration: Whenever we implement some external APIs from the web, sometimes it may also lead to abnormal behaviour due to network issues, response error or rate limits. In this case, using exceptions is also beneficial as you can implement the retry logic here.
Conclusion:
As we saw exception handling in C++ is very important.
It will help in the future when you interact with various kinds of large problems.
Exception handling helps us to assume the situation before even executing the code. It helps a lot to understand the situation.
Key Takeaways From The Article:
- An exceptional condition occurs in a program when your program behaves uncertainly or unexpectedly for various reasons.
- Handling these situations is necessary for an efficient execution of the code and easy debugging. This is where we make use of exception handling.
- You can handle exceptional conditions in C++ by using the try-catch method or by using the catch-all method.
- It is important to know what are the best ways you can perform exception handling to handle errors.
- We see the application of error and exception handling in different scenarios in our project.
