COMP 202 Lecture Notes - Lecture 18: Null Pointer, Bracket, Compile Time

• School: McGill University
• Department: Computer Science (Sci)
• Course: COMP 202
• Professor: Melanie Lyman- Abramovitch

Document Summary

There are three mains types : compile time errors, run time errors, logical errors. Generally, these are syntax" problems (missing semicolon, extra curly bracket, misspelled variable name, etc). These errors are caught at run time and often depend on input/the values of the variables. Array index out of bound (too large, too small) The values of a reference type of an address. If you create a variable that is a reference type (eg, an array) but you don"t initialize it to have a value, then there is no address there yet -> no value there yet -> the value is null. If you try to ask for the value at [0], and it hasn"t been initialized, then the value is null. They usually are not too terrible to track down because you get an error message from the computer. These errors will not cause the program to crash. But when you run your code, it just doesn"t work. ".