"C + +" reference parameter-reference parameter

1.reference parameter

The following two functions are equivalent and are only called in a different way:

1>

1 int Reset (int i) {2     i =; 3     return} 5  6 int{8 int j=0; 9 j = Reset (j); COUT&L t;<j<<endl;11 System ("PAUSE"); return 0;       

2>

1 void Reset (int &i) {2     i =} 4  5 int{7     int Reset (j); 9 Cout<<j<<
          
           ENDL;10 System ("PAUSE"
           ); return 0;  
             

function differences, the first must have a return value, the second does not have to.

Called when the difference is in line 9th.

The void reset () function references parameter I just another name of the variable J, which is essentially the variable J, which does not require a return value, and changing the contents of I is equivalent to changing the contents of J.

2. Implementing a function With reference parameters returns multiple results

As we all know, a function can only have one return value.

However, the effect of returning multiple results can be achieved by reference parameter.

1 //find the first occurrence of a character Pos, and draw a total number of occurrences occurs2 3#include <iostream>4 5 using namespacestd;6 7 string:: Size_type Find_char (Const string&s,CharCstring:: Size_type &occurs) {8Auto ret =s.size ();9Occurs =0;Ten      for(Decltype (ret) i =0; I<s.size (); ++i) { One         if(s[i]==B) { A             if(ret = =s.size ()) { -RET =i; -             } the++occurs; -         } -     } -     returnret; + } -  + intMain () A { at     strings ="CASUTXODOIHSDFD";  -     string:: Size_type occurs=0; -Cout<<find_char (s),'D', POS) <<Endl; -cout<<occurs<<Endl; -System"PAUSE"); -     return 0; in}

Output

7 3

Where occurs is the referenced parameter, its value is changed when the function is called.

"C + +" reference parameter-reference parameter