C++ how to pass an array to a function

pass an array

C++ doesn’t permit to pass a whole array as an associate degree argument to a perform. However, you’ll pass a pointer to the associate degree array by specifying the array’s name while not the associate degree index.

If you wish to pass a single-dimension array as an associate degree argument during a performance, you’d got to declare perform formal parameter in one amongst following 3 ways and everyone 3 declaration ways turns out similar results as a result of every tells the compiler that associate degree whole number pointer goes to be received.

In C, once we pass the associate degree array to a perform say fun(), it’s continually treated as a pointer by fun() as per programminggeeks.


Formal parameters as a pointer shows below:

void myFunction(int *param) {






Formal parameters showing as a sized array as follows −

void myFunction(int param[10]) {





Now, take into account the subsequent performance, which can take Associate in Nursing array as Associate in Nursing argument together with another argument and supported the passed arguments, it’ll come back an average of the numbers skilful the array as follows −

double getAverage(int arr[], int size) {

int i, sum = 0;

double avg;

for (i = 0; i < size; ++i) {

sum += arr[i];


avg = double(sum) / size;

return avg;


Therefore in C, we have a tendency to should pass the size of the array as a parameter. Size might not be required solely just in case of \0′ terminated character arrays, size will be determined by checking the finished string character.

Note that the character array on top of the program isn’t \0′ terminated. See this for details.

Now, we have a tendency tore a number of common approaches that we use however do one recognizes that there are super cool thanks to doing the same associated with this you may be ready to retain an identity of an array. we are going to speak concisely that at a very moment.


-A major disadvantage of on top of technique is compiler has no plan concerning what you’re passing. What I mean here is for compiler we have a tendency to area unit simply passing an int* and that we recognize that this is often to inform to array however compiler doesn’t recognize this.

-To verify my statement you’ll be able to decide for each loop on your array. you may, sure enough, get a slip-up speech no owed begin, finish operate found.

This is as a result of passing array is like really passing number pointer and it itself has no data concerning underlying array thence no iterator is provided.

Template Approach (Reference to Array):

This technique retains all data concerning the underlying array.

This technique is majorly supported relevance array however mistreatment this with templates optimizes our technique. templet dependency really calculates the length of array mechanically at the time of the call in order that it will be accustomed to produce a reference as a result of a relevance array should recognize the scale of an array.


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