The method of using the reference of Cstroke + as the return value of a function
The content of this article introduces the relevant knowledge of "Champact + reference as the method of function return value". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!
Syntax: type & function name (formal parameter list) {function body}
Pay special attention to:
1. When a reference is used as the return value of a function, the & must be preceded by the function name when defining the function
two。 The greatest advantage of using a reference as the return value of a function is that it does not produce a copy of the return value in memory
/ / Code source: RUNOOB
# include
Using namespace std
Float temp
Float fn1 (float r) {
Temp=r*r*3.14
Return temp
}
Float & fn2 (float r) {/ / & indicates that it returns a reference to temp, in other words, temp itself
Temp=r*r*3.14
Return temp
}
Int main () {
Float a=fn1 (5.0); / / case 1: return value
/ / float& b=fn1 (5.0); / / case 2: use the return value of the function as the initialization value of the reference [Error] invalid initialization of non-const reference of type 'float&' from an rvalue of type' float'
/ / (some compilers can compile the statement successfully, but will give a warning)
Float c=fn2 (5.0); / / case 3: returns a reference
Float & d=fn2 (5. 0) / / case 4: use the reference returned by the function as the initialization value of the new reference
Cout
