Errors

In the world of programming, errors are like the bumps in the road you encounter while driving. They are bound to happen, but they also teach you valuable lessons. In C++, errors come in various flavors, each with unique characteristics. Let's explore the main types of errors in C++ and how to deal with them.

Syntax errors

Syntax errors are the most common type of error in C++. They occur when the code violates the language's grammar rules. It's like trying to speak a language without proper grammar – it just won't make sense to the compiler. The compiler catches these errors and refuses to compile the code until you fix them.

#include <iostream>

int main() {
    std::cout << "Hello, World!" << std::endl
    return 0;
}

In this snippet, we missed a semicolon at the end of std::cout line. The compiler will scream at us, saying "expected ';' before 'return'."

Logical errors

When a program is compiled and run, it can produce unexpected results when specific input values are provided. These unexpected outcomes, which seem error-free but are incorrect, are referred to as logical errors. Logical errors are frequently made by programming beginners and are among the most common mistakes in programming. It's like making a sandwich but realizing you used peanut butter instead of jelly.

Let's take an example. We occasionally place a semicolon after a loop, which is syntactically correct but results in a single blank loop. It will then display the desired output.

#include <iostream>
  
int main() {
    int i;

    // Cause of Logical error
    for(i = 0; i <= 5; i++);
    {
        std::cout << "Hyperskill";
    }
        return 0;
}

The for loop iterates 5 times in the above example, but the output is only displayed once due to the semicolon at the end of the for loop. These are referred to as logical mistakes.

Runtime errors

Runtime errors occur while your program is running, like a car suddenly breaking down in the middle of a journey. In other words, errors that occur during program execution after successful compilation are called run-time errors. They are often caused by unexpected inputs, division by zero, or accessing an element of an array beyond its boundaries.

#include <iostream>

int main() {
    int x = 5;
    int y = 0;
    int z = x / y;
    
    std::cout << "Result: " << z << std::endl;
    return 0;
}

Here, dividing by zero doesn't cause a crash, but the result will be unpredictable.

#include <iostream>

int main() {
    int arr[5];
    arr[10] = 42; // Accessing an out-of-bounds array element
    return 0;
}

In this case, we're trying to access an array element that doesn't exist, leading to a runtime error.

Semantic errors

Semantic errors are subtle beasts. They don't trigger any error messages, but your program produces incorrect results. Think of it as ordering a cheeseburger but getting a chicken sandwich instead. Semantic mistakes arise when a sentence is syntactically correct but has no meaning. This is analogous to grammatical errors. A semantic error may arise if an expression is entered on the left side of the assignment operator.

#include <iostream>
  
int main()
{
    int a = 10, b = 20, c;
    a + b = c;
  
    std::cout << c;
    return 0;
}

Sources of error and its prevention

• Syntax errors typically happen when writing code that violates the language's grammar rules. Logic errors, on the other hand, can occur anywhere in your code and are often the result of flawed reasoning or incorrect calculations.
• Runtime errors can occur during the execution of your program and are often caused by unexpected inputs, division by zero, or accessing elements beyond array boundaries.
• Semantic errors can be challenging to spot because they don't trigger error messages but lead to incorrect results. They often arise when code appears syntactically correct but lacks meaning.

To minimize such errors in your C++ code, consider the following checklist:

• Choose a compiler known for its robust error-checking capabilities to catch syntax errors early in development.
• Use debugging tools that allow you to systematically step through your code, inspect variables, and identify logic errors.
• Incorporate error handling mechanisms to gracefully handle unexpected situations, ensuring your program doesn't crash or produce incorrect results. You'll learn to apply error-handling mechanisms in upcoming topics.
• Encourage code reviews and seek feedback from peers and experienced programmers. A fresh pair of eyes can often spot errors you might have missed.
• Adhere to established coding standards and best practices to reduce the likelihood of introducing semantic errors. Consistent and well-structured code is easier to maintain and less error-prone.

Conclusion

In conclusion, errors are an integral part of the learning process in C++ and programming in general. While they may seem frustrating at times, they are valuable teachers that help you sharpen your coding skills. The key is not to fear errors but to embrace them as opportunities to learn and improve your code.