for_each loop in C++
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”: #include<algorithm>, and hence has to be included for successful operation of this loop.
- 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 start_iter, InputIterator last_iter, Function fnc) start_iter : The beginning position from where function operations has to be executed. last_iter : The 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 or if any of the operations on iterators throws an exception, for_each loop will also throw an exception and break/terminate the loop.
- Invalid arguments may leads to Undefined behavior.
- For_each can not work with pointers of an array (An array pointer do not know its size, for_each loops will not work with arrays without knowing the size of an array)
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
With the introduction of lambda functions, this can be easily used to make the whole thing inline which is very compact and useful for people looking for using functional programming.
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