Code on pass by reference, pass by values, pass by address

Similar to parameter passing, a function can return in 3 ways

• Return by value
• Return by address
• Return by reference

 
Return by Value
 

int sum(int, int);

int main() {
  int a = 10, b = 20, c;
  c = sum(a, b);
  return 0;
}

int sum(int x, int y) {
  int z;
  z = x + y;
  return z;     
}
// z --> CPU reg like accumulator
// accumuator --> c

Return by Address
 

int *fetchp(void);

int main() {
  int *ptr = fetchp();
  //some code
  //access *ptr
  return 0;

}

int* fetchp(void) {
  int val = 100;
  return &val;
}

Return by Reference
 

#include <iostream>

int main() {
 int &ref = fetchr();
 //some code
 //access ref
 return 0;
}

int& fetchr(void) {
  int val = 100;
  return val;
}