What is the Difference Between Run Time Error and Syntax Error

The main difference between Run Time Error and Syntax Error is that the Run Time Error occurs due to performing an illegal operation while Syntax Error occurs due to a violation of a grammar rule when writing the program.

Errors can occur when writing programs. Basically, an error refers to an unexpected output of a program. Moreover, errors prevent the program from successfully executing. Therefore, it is an important task to remove the errors from the program. There are various types of errors and two of them are run time error and syntax error.

Key Areas Covered

1. What is Run time Error
    – Definition, Functionality
2. What is Syntax Error
   – Definition, Functionality
3. What is the Difference Between Run Time Error and Syntax Error
   – Comparison of Key Differences

Key Terms

Run Time Error, Syntax Error

What is Run Time Error

Run time error occurs due to performing an illegal operation. In other words, the computer detects these errors at the time of running the program. Run time error stops executing the program and a diagnostic message will display on the console with the details of that error.

Few run time errors are as follows. Assume there is an integer and the programmer divides that integer by zero. This is a run time error. Also, assume that there is an array in the program that stores five numbers (int array1[5]). Accessing the element array1[10] will give a run time error. Furthermore, accessing memory that is not available is also a run time error.

What is Syntax Error

When writing a program, the programmer should follow the proper standards and syntax of that language. Violating the grammar rules of the program can cause syntax errors. In other words, it is a mistake in the syntax of a sequence of characters or tokens when writing a program using a specific programming language.

The compiler detects the syntax errors while compiling the program.  It is easier to detect syntax errors because the compiler displays the location and the type of that error. It is not possible to successfully compile the program when there are syntax errors. Therefore, the programmer should fix them.

Missing the semicolons, missing curly braces, undeclared variables, misspelling keywords and identifiers are some examples of syntax errors. If the programmer just writes the statement without a semicolon, it is a syntax error. If the variable name is “number” but the programmer writes it as “num”, is a syntax error. Therefore, it is essential to write a program without any syntax error in order to successfully compile it.

Difference Between Run Time Error and Syntax Error

Definition

A runtime error is a program error that occurs while the program is running. Whereas, a syntax error is an error in the syntax of a sequence of characters or tokens that is intended to be written in a particular programming language. Thus, this is the main difference between Run Time Error and Syntax Error.

Cause

Another difference between Run Time Error and Syntax Error is their cause. A run time error occurs due to performing an illegal operation while a syntax error occurs due to a violation of one or more grammar rules.

Detection

Moreover, the computer detects a runtime error at the time of running the program while the compiler detects the syntax error at the time of compiling the program.

Examples

Array out of bound, diving by zero, accessing memory that is not available are some examples of runtime errors. Missing the semicolons, missing curly braces, undeclared variables, misspelling keywords and identifiers are some examples of syntax errors.

Conclusion

Various errors can occur when writing programs. Two of them are run time error and syntax error. The main difference between Run Time Error and Syntax Error is that the Run Time Error occurs due to performing an illegal operation while Syntax Error occurs due to a violation of a grammar rule when writing the program.

Reference:

1.Learners, Online. PGC Lectures: Programming Errors & Types, Syntax Error, Runtime Error, Logical Error, Online Learners, 8 Jan. 2017, Available here.
2.P2P (Peer To Peer) Definition, Available here.

Image Courtesy:

1.”Ahramic” By Rehoerigjoigjrtioj-Own work,(CC BY-SA 3.0) via Commons Wikimedia
2.”85017″ (CC0) via Pxhere