1 min read 231 words Updated Sep 24, 2026 Created Sep 24, 2026
#Programming

What are Errors?

Errors represent exceptional conditions or failures in program execution. They occur when the program encounters a state it cannot handle or when operations cannot complete successfully.

Why Errors Exist

  • Programs interface with external reality (I/O, network, user input)
  • Hardware has limits (memory, disk space)
  • User behavior is unpredictable
  • System state can change between operations

Categories of Errors

Syntax Errors

Caught at compile-time or during parsing.

  • Typos in keywords or variable names
  • Missing brackets, parentheses, or semicolons
  • Invalid language constructs
# Example: Missing closing parenthesis
print("Hello"  # Syntax error

Runtime Errors

Occcur during program execution.

  • Division by zero
  • Null/nil pointer dereference
  • Index out of bounds
  • Stack overflow
# Example: Division by zero
result = 10 / 0  # Runtime error

Logic Errors

Program runs but produces incorrect results.

  • Algorithm bugs
  • Wrong conditional logic
  • Off-by-one errors
# Example: Logic error - should be < not <=
for i in range(len(items)):
    if i <= len(items):  # Always true, will process one too many
        process(items[i])

I/O Errors

External system failures beyond program control.

  • File not found
  • Network timeout
  • Permission denied
  • Database connection lost

See Also