In C++ programming language, we can return a pointer from a function like any other data type. We have to declare return type of the function as pointer.
For Example :
int* getEvenNumbers(int N){
/* Function Body */
}
Points to Remember
As we know that, local variables gets created when control enters a function and gets destroyed as soon as control exits from a function. We should not return pointer to a local variable because as soon as control returns from a function the memory pointed by pointer no longer contains data of local variable.
If we want to return pointer to a local variable then we should declare it as a static variable so that it retains it's value after control exits from function.
As we know that, local variables gets created when control enters a function and gets destroyed as soon as control exits from a function. We should not return pointer to a local variable because as soon as control returns from a function the memory pointed by pointer no longer contains data of local variable.
If we want to return pointer to a local variable then we should declare it as a static variable so that it retains it's value after control exits from function.
C++ Program to return a pointer from a function
#include <iostream>
using namespace std;
// This function returns an array of N odd numbers
int* getOddNumbers(int N){
// Declaration of a static local integer array
static int oddNumberArray[100];
int i, odd = 1;
for(i=0; i<N; i++){
oddNumberArray[i] = odd;
odd += 2;
}
// Returning base address of oddNumberArray array
// As oddNumberArray is a static variable, it will
// retain it's value even after function exits
return oddNumberArray;
}
int main(){
int *array, counter;
array = getOddNumbers(10);
cout << "Odd Numbers\n";
for(counter=0; counter<10; counter++){
cout << array[counter] << " ";
}
return 0;
}
Output
Odd Numbers 1 3 5 7 9 11 13 15 17 19