When we are writing C++ programs, the compiler is our first line of defense against errors.

There are two types of compile-time errors:

• Syntax errors: Errors that occur when we violate the rules of C++ syntax.
• Type errors: Errors that occur when there are mismatch between the types we declared.

Some common syntax errors are:

• Missing semicolon ;
• Missing closing parenthesis ), square bracket ], or curly brace }

Some common type errors are:

• Forgetting to declare a variable
• Storing a value into the wrong type

Here’s an example of a compile-time error message:

The compiler will tell us where (line number) it got into trouble and its best guess as to what is wrong.