4 for_each loop

This loop is defined in the header file “algorithm”: #include, and hence has to be included for successful operation of this loop.m5K拜客生活常识网

该循环在头文件“算法”中定义：#include algorithm ，因此必须包含该循环才能成功运行。m5K拜客生活常识网

It is versatile, i.e. Can work with any container.m5K拜客生活常识网

它是多功能的，即可以与任何容器一起工作。m5K拜客生活常识网

It reduces chances of errors one can commit using generic for loopm5K拜客生活常识网

它减少了使用泛型for循环犯错的机会m5K拜客生活常识网

It makes code more readablem5K拜客生活常识网

它使代码更具可读性m5K拜客生活常识网

for_each loops improve overall performance of codem5K拜客生活常识网

for_ each循环提高了代码的整体性能m5K拜客生活常识网

syntax:m5K拜客生活常识网

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. 

code demo:m5K拜客生活常识网

#include#include#includeusing namespace std; // helper function 1void printx2(int a){    cout << a * 2 << " ";} // helper function 2// object type functionstruct Class2{    void operator() (int a)    {        cout << a * 3 << " ";    }} ob1; int main(){    // initializing array    int arr[5] = { 1, 5, 2, 4, 3 };    cout << "Using Arrays:" << endl;         // printing array using for_each    // using function    cout << "Multiple of 2 of elements are : ";    for_each(arr, arr + 5, printx2);         cout << endl;         // printing array using for_each    // using object function    cout << "Multiple of 3 of elements are : ";    for_each(arr, arr + 5, ob1);         cout << endl;         // initializing vector    vector arr1 = { 4, 5, 8, 3, 1 };    cout << "Using Vectors:" << endl;         // printing array using for_each    // using function    cout << "Multiple of 2 of elements are : ";    for_each(arr1.begin(), arr1.end(), printx2);         cout << endl;         // printing array using for_each    // using object function    cout << "Multiple of 3 of elements are : ";    for_each(arr1.begin(), arr1.end(), ob1);         cout << endl;}

Invalid arguments may leads to Undefined behavior.m5K拜客生活常识网

无效参数可能导致未定义的行为。m5K拜客生活常识网

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).m5K拜客生活常识网

For_ each不能处理数组指针（数组指针不知道其大小，For_each循环在不知道数组大小的情况下不能处理数组）。m5K拜客生活常识网

refm5K拜客生活常识网

https://www.geeksforgeeks.org/loops-in-c-and-cppm5K拜客生活常识网

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