Logical errors:

The Logical errors are more complicated to locate, as they do not result in any error message. The logical error is a mistake in reasoning by the programmer, but it is not a fault in the programming language. An illustration of a logical error would be dividing by 2.54 rather than of multiplying in order to convert inches to centimeters. The outcome printed or returned would be wrong, but this may not be obvious.

All the programs must be robust and must wherever possible anticipate potential errors, and guard against them. For illustration, whenever there is input into a program, the program must error-check and make sure that the input is in the accurate range of values. Also, before dividing, the denominator must be checked to make sure that it is not zero.

In spite of the best precautions, there are bound to be errors in the programs.