computer programming errors

Programming Errors: The Three Most Common Types

Errors in computer science are common. Everyone involved in computer programming will make them, at any point in their career, although it is normal that beginners will be particularly prone to them while they learn and develop their skills. When they happen, the programmer needs to chase them down until he finds all of them, so that the software can function properly. Here are the three most common types of errors in programming.

Difficulties in Tracking and Solving Programming Errors

Coding is something that can be learned, but we could say that those who are extremely good, practice it almost like an art form. However, anyone who creates a new program will have to face the phase where you click on “run” and… nothing happens. Or if it does run, the results are not what the programmer was looking for. That is when he will need to look for errors in the program, which can be quite bewildering and stressful.

What helps the developers knowing where to look for the problem is by separating them in three types of programming errors. That way, he can go through them, one by one, on the look-out for the false code and then correct it. It is not a miraculous solution, but it provides the programmer with a much better chance of solving the issue. Here are the three most common types of programming errors, which are by categories: Logical, syntax and semantic errors. Keep in mind that, to complicate the matter, all of them can be either static (compile-time) or dynamic (run-time) in nature.

First: Look for Logical Errors

Logic in a program is as important as logic in our day-to-day lives. It is, as well, as complicated to find them when they happen. A logical error will not stop the program for running or cause it to crash; it will make it behave in a way it is not supposed to. Therefore, it is quite possible that you won’t recognize that there is an error in the programming until later on, when you notice something strange or unexpected. The problem being that a logical error still makes sense for the program; it just makes it do something you did not want it to do.

One of the logical errors is null reference. They are often the source of most of the potential application bugs. They happen when computer logic has not been followed. And though they are usually quite simple, it can be a real nightmare to try to find where the logic went wrong. In this situation, it can be that a property or a field is null, that a condition stopped an object from being created, or that a local variable field is indicated but never initialized.

Second: Look for Syntax Errors

When you find yourself with a syntax error, it means that there is an incorrect sequence in the computer language. You will notice this type of error at different times, depending of the language used. In compiled languages, they will show-up at compile time, while in interpreted languages they will happen when you run the program. In this case, the error message might not even indicate that it is a syntax issue, which will send you in search of a problem without any clue of what it could be.

Syntax errors are like spelling mistakes. They can involve a single-digit that needs to be reviewed or corrected. Logical errors usually imply that you will need to review a whole section of a code. A few of the most common syntax errors are: missing semicolons ending a line and or extra/missing bracket at the end of a function.

Third: Look for Semantic Errors

If the programming error you are looking for has not yet been found, after searching through the two previous categories, it is time to look for a semantic error. They imply an improper use of program statements. If you have made a semantic error, the result will be that there is simply no result. A semantic error will need to be found, taken out and rewritten in another way that makes sense to the computer.


Most programming errors are usually solved by looking into these three categories and finding the culprit before recoding. Just so you understand the differences between them, let’s summarize by comparing them to real life:

A semantic error refers to the meaning (context). In real life, it would be similar to you using a word in the wrong place in a sentence, making it unintelligible. In a computer form, it means confusing a metric with an imperial input value.

In comparison, the syntax errors are “spelling and grammar” issues. In a written form, it would be like forgetting to close a parenthesis at the end of a sentence or not placing a comma.

Finally, a logical error has to do with how the program will flow and create the end result (or not) that you want it to. In real life, it would mean that you use a particular logic in order to obtain what you desire. However, that logic would be flawed, and the result would be different than the one you intended.

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