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Passing array to a function cpp code

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 This Cpp Tutorial contains
  • 3 ways to pass an array to a function
  • Each way and its usage
  • 3 c++ codes examples
  • How codes are working 
  • Sample output
  • Compiler used "C++ CodeBlocks Compiler"

Write a program which declares an array, initialize it then pass to a function. Function takes square of array values and update it. Show updated values in main function.

Concept used:
How programs works
  •   Declare array of size 10
  •   Initialize it using for loop
  •   Calling "UpdateArray" function and passing array as           argument
  •   Take squares of all values and update it
  •   Display final result in main function
 
Note: Function return type is void why? 
          As we know array name is constant pointer memory location if we get this location we can update it after updating if we access this memory location any where in the program we will get updated values. So no necessarily needs to return array or pointer.

First way
As we know array name is a constant pointer if we can get the this pointer we can access all values of array.
declaring  array in function parameter
Prototype: void  UpdateArray(int array[] );

 c++ code

  1.  #include <iostream>
  2.  using namespace std;
  3.  void UpdateArray(int array[])
  4.  {
  5.      for(int i=0;i<=9;i++)
  6.           array[i]=array[i]*array[i];
  7.  }
  8.  int main()
  9.  {
  10.      int array[10];
  11.      for(int i=0;i<=9;i++)
  12.           array[i]=i+1;
  13.      UpdateArray(array);
  14.  // Updated Values of Array
  15.      for(int i=0;i<=9;i++)
  16.           cout<<array[i]<<endl;
  17.      return 0;
  18.  }


Second way
Prototype: void  UpdateArray(int *array );
Declaring an integer pointer in function parameter
This pointer will receive arrays name(constant pointer) and we can access all values and update too.

  1.   #include <iostream>
  2.  using namespace std;
  3.  void UpdateArray(int *array)
  4.  {
  5.      for(int i=0;i<=9;i++)
  6.           array[i]=array[i]*array[i];
  7.  }
  8.  int main()
  9.  {
  10.      int array[10];
  11.      for(int i=0;i<=9;i++)
  12.           array[i]=i+1;
  13.      UpdateArray(array);
  14.  // Updated Values of Array
  15.      for(int i=0;i<=9;i++)
  16.           cout<<array[i]<<endl;
  17.      return 0;
  18. }


Third way
 In this way we pass two arguments one is arrays name and second   is its size
 In function receiving parameters we declares an array or integer pointer (your choice) to receive address of array and another integer variable size which contains the size of array.
Prototype:  void  UpdateArray(int *array, int size );

  1.  #include <iostream>
  2.  using namespace std;
  3.  void UpdateArray(int *array, int size)
  4.  {
  5.      for(int i=0;i<size;i++)
  6.           array[i]=array[i]*array[i];
  7.  }
  8.  int main()
  9.  {
  10.      int array[10];
  11.      for(int i=0;i<=9;i++)
  12.           array[i]=i+1;
  13.      UpdateArray(array,10);
  14.  // Updated Values of Array
  15.      for(int i=0;i<=9;i++)
  16.           cout<<array[i]<<endl;
  17.      return 0;
  18.  }
 Sample output all the codes have same
passing array to a function cpp code different ways
more Arrays Examples Here
C++ Simple Examples
For best practice do experiment with codes and examine output

if any confusion found dry run the code on a paper.

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