Error Analysis:

Error: Uncertainty in the measurement of physical quantity is called error. For example true value for given length is 4 cm but one student measures it as 3.9 and other is 4.1 . In this case -0.1 and 0.1 is called error in measurement of length.
Errors are of different types as follows:
Instrumental Errors:Errors occur dur to using improper instrument means instrument which is used to measure the length is not correct.
Constant Errors: Errors which are occurred each time of the same sign. It is called constant error.
Personnel Error: This type of error occurred when the person is not measuring the length accurately. It is the error due to carelessness of the person in measuring the length.
Random Errors: Errors occurred due to unknown changes which are not controlled are called random errors.The reasons due to which errors are occurred are not known therefore these type of errors can't be controlled.
Environmental Conditions:Errors occurred due to change in temperature and pressure are called errors due to environmental conditions.For example in summer length of metallic scale is increased than in winter season.
Systematic Error: Systems which results each time an error of fixed amount are. these errors are called systematic errors.
Significant Figures:The figure with fixed value plus one uncertain value is called significant figure. For example one person is measuring the length as 3.9cm and other is 3.8 and other one is 3.7 . Each time 3 is a fix digit and .8 , .7 , .9 are uncertain digit . Therefore these are significant numbers.

Errors in programming:
Syntax Error: While writing a program often programmer misses a small symbols which causes errors when the program is complied. Error occur during compilation of a program is called syntax error.For example: error during coding in java-System.out.println(a)  
In the above code ; is missed in the end of line due to which this code will generate syntax error.correct code is as:  System.out.println(a);
Run time Error:Once the program is successfully compiled by complier .Now it is the turn of interpreter to run the program.But if we have applied a wrong logic in the program it will generate run time error.For example division by zero.