How do You Throw and Catch Exceptions in C to Handle Invalid Inputs?

Exception Handling: Throwing Exceptions in C

Exception handling is a crucial technique in C that allows you to manage errors and unusual situations effectively. Understanding how to throw, try, and catch exceptions is essential for writing robust and reliable code.

One common scenario where exceptions are useful is when you want to handle invalid inputs or conditions that should not occur during normal program execution. For instance, let's consider a function compare(int a, int b) that compares two integers.

To handle the case where either a or b is negative, we can modify the definition of the compare function as follows:

#include <stdexcept>

int compare(int a, int b) {
    if (a < 0 || b < 0) {
        throw std::invalid_argument("received negative value");
    }
}

In this example, we use the throw statement to raise an exception if either parameter is negative. The std::invalid_argument is a built-in exception object that corresponds to an invalid argument being passed to a function.

To handle the exception thrown by the compare function, we can use a try-catch block:

try {
    compare(-1, 3);
} catch (const std::invalid_argument& e) {
    // Handle the exception here...
}

Within the try block, we attempt to execute the compare function with potentially invalid inputs. If an exception is thrown, the catch block catches it, giving us a reference to the exception object e. We can use this object to determine the cause of the exception and take appropriate action.

Additionally, C provides flexibility in exception handling. You can throw by value and catch by reference, as demonstrated in the example above. You can also re-throw exceptions or catch exceptions regardless of type using catch(...). These features empower you to handle exception scenarios in a customized and efficient manner.

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