C++ Passing Array to a Function

Arrays can be passed to a function as an argument. Read this example to pass one-dimensional array to a function:

Example 1: Passing One-dimensional Array to a Function

C++ Program to display marks of 5 students by passing one-dimensional array to a function.

#include <iostream>
using namespace std;
void display(int marks[5]);

int main() {
    int marks[5] = {88, 76, 90, 61, 69};
    display(marks);
    return 0;
}

void display(int m[5]) {
    cout<<"Displaying marks: "<<endl;
    for (int i = 0; i <5; ++i) {
        cout<<"Student "<<i+1<<": "<<m[i]<<endl;
    }
}

Output

Displaying marks: 
Student 1: 88
Student 2: 76
Student 3: 90
Student 4: 61
Student 5: 69

When an array is passed as an argument to a function, only the name of an array is used as argument.

display(marks);

Also notice the difference while passing array as an argument rather than variable.

void display(int m[5]);

The argument used marks in the above code represents the memory address of first element of array marks[5]. And the formal argument int m[5] in function declaration decays to int* m;. That's why, although the function is manipulated in the user-defined function with different array name m[5], the original array is manipulated. The C++ programming language handles passing array to a function in this way to save memory and time.

Note: You need to have understanding of pointers to understand passing array to a function. Learn more: Call by reference

Passing Multidimensional Array to a Function

Multidimensional array can be passed in similar way as one-dimensional array. Consider this example to pass two dimensional array to a function:

Example 2: Passing Multidimensional Array to a Function

C++ Program to display the elements of two dimensional array by passing it to a function.

#include <iostream> 
using namespace std;
void display(int n[3][2]);

int main() {
        int num[3][2] = {
        {3, 4},
        {9, 5},
        {7, 1}

    };
    display(num);
    return 0;
}
void display(int n[3][2]) {

    cout<<"Displaying Values: "<<endl;
    for(int i = 0;  i < 3; ++ i) {
        for(int j = 0; j < 2; ++j) {
            cout<<n[i][j]<<" ";
        }
    }
}

Output

Displaying Values: 
3 4 9 5 7 1 

Multidimensional array with dimension more than 2 can be passed in similar way as two dimensional array.