Apart from the generic looping techniques, such as “for, while and do-while”, C++ in its language also allows us to use another functionality which solves the same purpose termed “for-each” loops. This loop accepts a function which executes over each of the container elements. This loop is defined in the header file “algorithm”, and hence has to be included for successful operation of this loop.
- Why to use for_each?
- It is versatile, i.e can work with any container.
- It reduces chances of errors one can commit using generic for loop
- It makes code more readable
- for_each loops improve overall performance of code
for_each (InputIterator first, InputIterator last, Function fn) strt_iter : The beginning position from where function operations has to be executed. last_iter : This ending position till where function has to be executed. fnc/obj_fnc : The 3rd argument is a function or an object function which operation would be applied to each element.
Using Arrays: Multiple of 2 of elements are : 2 10 4 8 6 Multiple of 3 of elements are : 3 15 6 12 9 Using Vectors: Multiple of 2 of elements are : 8 10 16 6 2 Multiple of 3 of elements are : 12 15 24 9 3
Exceptions and for_each
In the cases of exceptions, if the function throws an exception, for_each loop will also throw an exception and break/terminate the loop.
Using Array 2 10 4 The Exception element is : 2 3 15 6 The Exception element is : 2 Using Vector 2 6 12 The Exception element is : 6 3 9 18 The Exception element is : 6
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