12 Es 26 - Arrays On Functions

Arrays on Functions 12

Introduction to Programming

Assignment Operator • Assignment operator does not work on arrays as it is on variables. … int a[] = {1,2}, b[] = {2,3,4}; b = a; …

• b and a now refer to the same array which was originally just a. • A change in either reflects to both. Introduction to Programming

Passing Arrays to Functions • A function that accepts an int array as parameter is declared as follows: change_array(int formal[], int size);

• Note that change_array has no way of knowing formal's size (number of elements) just by the array itself. • Passing an array to the above function can be illustrated as follows: int actual[2] = {1,2}; change_array(actual,2); Introduction to Programming

Passing Arrays to Functions • Arrays are passed to functions by reference i.e. using the assignment operator =. • Hence, any change in formal is also a change in actual.

Introduction to Programming

Copying Arrays • Can be done by copying each element to the destination array using a loop. • A more efficient way is to use the function memcpy declared in string.h int source[] = {1,2}, dest[4]; memcpy(dest, source, sizeof(int)*2); Introduction to Programming

Returning Arrays 

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Forces us to learn pointers which deals with memory addresses. Let's not do that, yet. An array can directly be modified by a function when passed, so we can think of it as some kind of a “return” mechanism.

Introduction to Programming