Template:Computer Programming/Error Handling/5
The great strength of exceptions handling is that it can block several operations within one exception handler. This eases up the burden of error handling since not every function or procedure call needs to be checked independently for successful execution.
Design by Contract 
In Design by Contract (DbC) functions must be called with the correct parameters. This is the caller's part of the contract. If the types of actual arguments match the types of formal arguments, and if the actual arguments have values that make the function's preconditions True, then the subprogram gets a chance to fulfill its postcondition. Otherwise an error condition occurs. Now you might wonder how that is going to work. Let's look at the example first: