Differ pass by value and reference c++ example

Pass by value in C++ Programming
In this method we call a function by passing a value. A new copy of value is made and send to functions body. Where operations are applied on new copied value.




Advantages

• New copy is made of value after passing so if changes go wrong the original data will be save
• It increase the security of data

Disadvantage

• If the data is huge making too much copies may cause system over head.

Pass by reference in C++ Programming

In this method we call a function by its reference using address operator. It don't make a copy of data and pass the address of value to the function. Where operations are applied on the reference of value and changes made permanently to data.

Advantages

• When data is large it reduce the copies of data and creates less system overhead.

Disadvantage

• Security of data can be weak because the real information is accessible and can be changed 

C++ function example of both ways pass by value and pass by reference

In this example there are two functions one calculates a cube of number with value and other calculates cube of number with reference. With value returns result and with reference not return result.

#include<iostream>
using namespace std;

int pass_Value(int);
void pass_reference(int &);
int main()
{
    int num1,num2;

    cout<<"Enter First Number: ";cin>>num1;
    cout<<"Enter Second Number: ";cin>>num2;

    cout<<"\n\n\n";

    int result=pass_Value(num1);
    cout<<"\t\tPass By Value Result: "<<result<<endl;

    pass_reference(num2);
    cout<<"\t\tPass By Reference Result: "<<num2<<endl;

    return 0;

}

int pass_Value(int number)
{
    return (number*number*number);
}

void pass_reference(int &number)
{
    number=number*number*number;
}

Read also: C++ pointer example with pass by reference

Input Output Example:

see also: Learn Pointers in C++ Programming with Examples


Explanation of functions

• First function is simple we received a value calculate its cube and return simply the new result.
• In second function we applies changes using reference of number we sent so no need to return here. As changes are made permanently.

See More Examples Here: C++ Simple Examples

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c++ program to find area of circle using functions

Cpp tutorial to calculate area of circle

•  User enter radius or diameter of circle.
•  Program should have two functions one which takes radius as parameter and second takes diameter as parameter.
•  If user enters wrong option then tell users its valid selection and chose again the right option.

This Cpp Tutorial covers the concept of

• if else if statement
• for loop
• function with parameter and return value

Cpp code compiler used: Codeblocks C++ Compiler

#include <iostream>
#define PI 3.14159
using namespace std;

float AreaOfCircle(float radius);
float AreaWithDiameter(float diameter);

int main()
{
    float radius,diameter,circleArea;
    char choice='0';
    cout<<"\n\t\t\tFind Area Of Circle:"<<endl;


    for(;choice!='1'&&choice!='2';)
        {
         cout<<"\nEnter 1 to Enter Radius OR
                 2 to Enter Diameter: ";
         cin>>choice;
         if(choice!='1'&&choice!='2')
         cout<<"\n\t\tEnter a VALID Option ";

        }

    if(choice=='1')
    {
    cout <<"\n\t\tEnter Radius To Find Area: ";
    cin>>radius;
    circleArea=AreaOfCircle(radius);
    }
    else if(choice=='2')
    {
    cout <<"\n\t\tEnter Diameter To Find Area: ";
    cin>>diameter;
    circleArea=AreaWithDiameter(diameter);

    }
    cout<<"\n\n\t\tArea of Circle is:->> "<<circleArea<<endl;
    return 0;
}

float AreaOfCircle(float radius)
{
    return (PI*(radius*radius));

}

float AreaWithDiameter(float diameter)
{

    return (AreaOfCircle(diameter/2));
}

output of program

Program explanation

• Program has two functions one for radius and one for diameter both called upon user choice
• Both calculates the radius and diameter according to formula and return result value from where they have called
• A for loop is used to prevent the wrong choice selection it will break only if user enters valid option 1 or 2 else it will continue to ask user to enter valid option

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Cpp Function to Find Largest and smallest number in array

This Cpp tutorial contains

• Cpp array with random integer values
• Passing array to function
• if statement with in for loop
• Calculate result in function and display

 Compiler used: CodeBlocks Cpp Compiler

Write a program which generates some random number and store in array after it program pass array to a function which calculates maximum and minimum number in array and display it use any Cpp Compiler to code.

How program works

• Declare array of size 10
• Using for loop assign array indexes with random values between 1 and thousand
• Call the function and pass array and its size as argument
• Function declares two integers max and min and assign both integers with arrays first index value
• Then with in for loop there are two if condition first check is for minimum number and second check is for maximum number
• Finally program display the output values of both integers min and max

      Cpp Code

1.  #include <iostream>
2. #include <stdlib.h>
3. using namespace std;
4. void FindMaxMin(int *array, int size)
5. {        int min,max;
6.          min=max=array[0];
7.          for(int i=0;i<size;i++)
8.          {
9.              if(array[i]<min)
10.                min=array[i];
11.             else if(array[i]>max)
12.                max=array[i];
13.          }
14.  cout<<"Minimum Number  = "<<min<<endl;
15.  cout<<"Maximum Number = "<<max<<endl;
16. }
17. int main()
18. {
19.     int array[10];
20.     for(int i=0;i<=9;i++)
21.         {
22.          array[i]=rand()%1000+1;
23.          cout<<"array ["<<i<<"]"<<"= "<<array[i]<<endl;
24.         }
25.     FindMaxMin(array,10);
26. return 0;
27. }

 Sample Output

Another Example without Function more simple
Find Maximum and Minium Number in Array Cpp Code

More Cpp Program Tutorials
C++ Simple Examples

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