C + + summary function parameter, which returns a const object and a non-const object

Non-reference formal parameters

//交换函数，传递的实参只是参数的副本。并不能起到交换作用void swap(intint b) {    int m  = a;    a = b;    b = m;}

Pointer parameters

//可以起到交换作用void swap(int*aint*b) {    intm  *a;    *a*b;    *bm;}

Reference formal parameters

//可以起到交换作用void swap(intint &b) {    int temp = a;    a = b;    b = temp;}

Const formal Parameter

modifying parameters with const to avoid modification of arguments

string::size_type length(conststring &str) {    return str.size();}

Using arrays as formal parameters

//1void m(int a[]) {    cout << a[0] <<  endl;}//2void m(int *a) {    a[03;    cout << a[0] <<  endl;}int a[] = {123};m(a);

You can also use the const array parameter
General use of non-const formal parameters, the actual participants copied a copy of the delivery.
But for arrays, the array is silently converted to pointers, and parameter passing is a copy of the pointer, pointing to the first element of the array, changing the value, and changing the value of the array element.

Returns a non-const object

Copy a copy of the object you want to return back to

conststring getString(conststringconststring &str2) {    return str1.size() < str2.size()? str1 : str2;}

Returns the Cons object

No replication returns the original object directly, but never return a reference to the local object, because the function finishes running the objects to be destroyed

conststring &getString(conststringconststring &str2) {    return str1.size() < str2.size()? str1 : str2;}

C + + summary function parameter, which returns a const object and a non-const object