Explain what error messages are and give examples.

Error messages are notifications displayed by a computer program or system to inform the user that an unexpected or incorrect situation has occurred. These messages help users identify and troubleshoot issues that may be preventing the program from functioning properly.

Examples of error messages include:

1. "404 Not Found" - This error message is commonly displayed when a user tries to access a webpage that does not exist or cannot be found on the server.

2. "Invalid username or password" - This error message is often shown when a user enters incorrect login credentials while trying to access a secure system or website.

3. "Out of memory" - This error message indicates that the program has run out of available memory to perform a specific task, causing it to crash or freeze.

4. "File not found" - This error message appears when a program cannot locate a specific file or resource that it needs to function properly.

5. "Connection timed out" - This error message occurs when a program or device is unable to establish a connection with a server or network within a specified time frame.

Error Messages

Error messages are notifications that provide information about errors encountered by a computer program or system. They help identify the cause of the issue and suggest potential solutions.

Types of Error Messages:

- Syntax Errors: Occur when there are errors in the code syntax, such as missing punctuation or incorrect variable names.
- Semantic Errors: Occur when the code is syntactically correct but contains logical errors, such as using an invalid variable or function.
- Runtime Errors: Occur when the program encounters an unexpected state during execution, such as an out-of-bounds array access or an invalid file path.
- System Errors: Indicate problems with the operating system or hardware, such as low memory or a disk failure.

Examples of Error Messages:

Syntax Error:
- `SyntaxError: missing closing parenthesis`

Semantic Error:
- `TypeError: 'int' object is not iterable`

Runtime Error:
- `IndexError: list index out of range`
- `FileNotFoundError: [File Name] not found`

System Error:
- `MemoryError: memory exhausted`
- `IOError: [Disk Drive]: device not found`

Importance of Error Messages:

Error messages are crucial for debugging and troubleshooting software. They provide:

- Cause Identification: Help developers pinpoint the exact location and cause of the error.
- Solution Assistance: Suggest potential solutions to resolve the issue.
- Documentation: Provide a record of errors encountered and their resolutions, aiding future development and support.
- Error Prevention: Enable developers to anticipate and handle potential errors, improving the robustness of the software.