MATLAB Error Control Statement-try, catch

MATLAB define some functions that are used to control error. The try-catch statement is an error control function, which is explained below.

Try – catch statement

Try-catch statement provides error handling control. General form of the try-catch statement is

Syntax:

Statements between try and catch execute first. If no error appears in executing statements between try and catch, MATLAB further executes the statements/code after the end keyword. If an error occurs during the execution of statements between try and catch, MATLAB executes statements between catch and end. Try-catch statement can be explained with the help of the following example.

Example:

Output:

    MException with properties:        identifier: 'MATLAB:catenate:dimensionMismatch'         message: 'Dimensions of arrays being concatenated are not consistent.'           cause: {0×1 cell}           stack: [3×1 struct]      Correction: []  

Following are the points while using a try/catch statement in MATLAB:

• The control of the program execution first enters the try block and executes each statement.
• If any error occurs during the execution, then the control immediately passes to the catch block, leaving any other statements of the try block unexecuted.
• If there is no error occurs inside try block, then the control doesn’t enter the catch block. The control then reaches to the statements after the end keyword of try/ catch block.
• Whenever any error or exception occurs in the try block, the MATLAB constructs an instance of the MException class and returns the object in the catch statement.
• The MException class object can be accessed with the variable ME.
• The MException class object has five properties-identifier, message, stack, cause, and Correction. These properties describe details about the occurred exception.
• We can’t use multiple catch block, only one catch block within a try block is allowed.
• We can use nested try/catch blocks if required.

Example showing MException class object properties:

Output:

causeException =     MException with properties:        identifier: 'MATLAB:mycode:dimensions'         message: 'dimension mismatch occured: First argument has 4 columns, while second argument has 3 columns.'           cause: {}           stack: [0×1 struct]      Correction: []  

Program Termination

Program termination control allows to exit from our program at some point before its normal termination point.