Catch All

Overview

Sometimes you don't know exactly what type of exception might be thrown by third-party code. The catch-all block `catch(...)` acts as a safety net to catch literally anything.

Syntax

cpp

try {
    // Risky code from an external library
    externalLibraryCall();
} 
catch (int e) {
    cout << "Caught int exception";
}
catch (...) { // The ellipsis (...) means 'catch anything else'
    cout << "Caught an unknown exception!";
}

Common Pitfalls

You cannot access the exception object in a `catch(...)` block because it has no named parameter. You know an error happened, but you don't know what it is.

Interview Tips

A `catch(...)` block MUST be the very last catch block in a sequence. If you put it first, it will catch everything, and specific catch blocks below it will never run.

Real-World Example

Fallback mechanism for unknown failures.

example

cpp

#include <iostream>
using namespace std;

int main() {
    try {
        throw 3.14; // Throwing a double
    } 
    catch (int e) {
        cout << "Caught Int\n";
    }
    catch (char c) {
        cout << "Caught Char\n";
    }
    catch (...) {
        cout << "Caught something completely unexpected!\n";
    }
    return 0;
}

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