C++ Tutorial/Pointer/pointer reference

Use a reference parameter.

<source lang="cpp">#include <iostream> using namespace std;

void neg(int &i); // i now a reference

int main() {

 int x;
  
 x = 10;
 cout << x << " negated is ";
  
 neg(x); // no longer need the & operator
 cout << x << "\n";
  
 return 0;

}

void neg(int &i) {

 i = -i; // i is now a reference, don"t need *

}</source>

Use reference type eliminates the more confusing pointer notation.

<source lang="cpp">#include <iostream> using namespace std; struct stStudent {

char   pszName[66],
       pszAddress[66],
       pszCity[26],
       pszState[3],
       pszPhone[13];
int    icourses;
float  GPA;

}; void vByValueCall (stStudent stAStudent); void vByVariableCall (stStudent *pstAStudent); void vByReferenceCall (stStudent &rstAStudent); int main(void) {

stStudent astLargeClass[100];
 
astLargeClass[0].icourses = 10;
vByValueCall( astLargeClass[0]);
cout << astLargeClass[0].icourses << "\n"; // icourses still 10
vByVariableCall(&astLargeClass[0]);
cout << astLargeClass[0].icourses << "\n"; // icourses = 20
vByReferenceCall( astLargeClass[0]);
cout << astLargeClass[0].icourses << "\n"; // icourses = 30

}

 void vByValueCall(stStudent  stAStudent)

{

stAStudent.icourses += 10;    // normal structure syntax

} void vByVariableCall(stStudent *pstAStudent) {

pstAStudent->icourses += 10;  // pointer syntax

} void vByReferenceCall(stStudent &rstAStudent) {

rstAStudent.icourses += 10;   // simplified reference syntax

}</source>

uses reference parameters to swap the values of the variables it is called with

<source lang="cpp">#include <iostream> using namespace std;

void swap(int &i, int &j);

int main() {

 int a, b, c, d;
  
 a = 1;
 b = 2;
 c = 3;
 d = 4;
  
 cout << "a and b: " << a << " " << b << "\n";
 swap(a, b); // no & operator needed
 cout << "a and b: " << a << " " << b << "\n";
  
 cout << "c and d: " << c << " " << d << "\n";
 swap(c, d);
 cout << "c and d: " << c << " " << d << "\n";
  
 return 0;

}

void swap(int &i, int &j) {

 int t;
  
 t = i; // no * operator needed
 i = j;
 j = t;

}</source>