computer programming: c++ experiment #7 arrays part...

The Islamic University of Gaza

Engineering Faculty

Department of Computer Engineering

Fall 2017

ECOM 2003

Muath i.Alnabris

Computer Programming: C++

Experiment #7

Arrays Part II

Experiment #7:Arrays

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Passing Array to a Function

At some point, we may need to pass an array to a function as a parameter. In C++, it is not

possible to pass the entire block of memory represented by an array to a function directly as

an argument. But what can be passed instead is its address. In practice, this has almost the

same effect, and it is a much faster and more efficient operation.

To accept an array as parameter for a function, the parameters can be declared as the array

type, but with empty brackets, omitting the actual size of the array. For example:

void procedure (int arg[])

This function accepts a parameter of type "array of int" called arg. In order to pass to this

function an array declared as:

int myarray [40];

it would be enough to write a call like this:

procedure (myarray);

Example 1: Passing One-dimensional Array to a Function


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In the code above, the first parameter (int arg[]) accepts any array whose elements are of

type int, whatever its length. For that reason, we have included a second parameter that

tells the function the length of each array that we pass to it as its first parameter. This

allows the for loop that prints out the array to know the range to iterate in the array

passed, without going out of range.

Example 2: Passing Multidimensional Array to a Function

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


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In the above program, the multi-dimensional array num is passed to the function display.)(

Inside, display() function, the array n (num) is traversed using a nested for loop.

The program uses 2 for loops to iterate over the elements inside a 2-dimensional array. If it

were a 3-dimensional array, you should use 3 for loops.

Finally, all elements are printed onto the screen.

Note: Multidimensional array with dimension more than 2 can be passed in similar way as

two dimensional array.

Scope of variables:

A scope is a region of the program and broadly speaking there are three places, where

variables can be declared

− Inside a function or a block which is called local variables,

- In the definition of function parameters which is called formal parameters

- Outside of all functions which is called global variables.


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This section special with function

Pass By Reference:

The call by reference method of passing arguments to a function copies the reference of an

argument into the formal parameter. Inside the function, the reference is used to access

the actual argument used in the call. This means that changes made to the parameter affect

the passed argument.

To pass the value by reference, argument reference is passed to the functions just like any

other value. So accordingly you need to declare the function parameters as reference types

as in the following function swap(), which exchanges the values of the two integer variables

pointed to by its arguments.

For now, let us call the function swap() by passing values by reference as in the following

example –


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When the above code is put together in a file, compiled and executed, it produces the

following result –


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Lab work:

1- Write function to display a matrix as shown below. The diagonal of the matrix fills with 0. The

lower side fills will -1s and the upper side fills with 1s.

2- Write program Take a numbers from user and insert a random new values in array

Then write function to sort this numbers


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Homework:

1- Write program multiple two matrices using function, saves it in another matrix (two-

dimensional array) and displays it on the screen.

2- write C++ program to display a table of numbers as shown below:

computer programming: c++ experiment #7 arrays part...

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