Chapter 7, Problem 1P

Write a function named firstLast2 that takes as input an array of integers and an integer that specifies how many entries are in the array. The function should return true if the array starts or ends with the digit 2. Otherwise it should return false. Test your function with arrays of different length and with the digit 2 at the beginning of the array, end of the array, middle of the array, and missing from the array.

Program Plan Intro

Definition of function “firstLast2()”

Program Plan for “firstLast2()” function:

• The function “firstLast2()” should declared before it defined in a program.
• Define the function with its argument.
  • One argument is to get array values and another one is to define the size of the array.
  • Using “if…else” condition, check the array beginning and end value “2” or not.
    • If the condition is true, return “true” to calling function.
    • Otherwise return “false” to calling function.

Program Plan for testing code:

• Include the appropriate headers into program.
• Define the “firstLast2()” function.
• Define the “main()” method.
  • Initialize the arrays with a value “2” at starting, ending, and middle position of arrays.
  • Call the “firstLast2()” function with resultant value using “if…else” condition.
  • Print the appropriate statement on screen.

Program Description Answer

Program Description:

The following C++ program to define the “firstLast2()” function with a testing method.

Explanation of Solution

Function definition:

//Function definition with bool type

bool firstLast2(int arr[],int size)

{

//Condition

if(arr[0]==2||arr[size-1]==2)

{

/*Return true to calling Function*/

return true;

}

//Else statement

else

{

/*Return false to calling Function*/

return false;

}

}

Testing code:

//Include the appropriate headers

#include <iostream>

using namespace std;

//Function definition with bool type

bool firstLast2(int arr[],int size)

{

//Condition

if(arr[0]==2||arr[size-1]==2)

{

/*Return true to calling Function*/

return true;

}

//Else statement

else

{

/*Return false to calling Function*/

return false;

}

}

//Main method

int main()

{

/*Initialization of arrays with different length*/

int a1[5]={2,5,6,5,1};

int a2[4]={5,6,1,2};

int a3[7]={6,4,5,2,5,1,1};

int a4[3]={6,5,1};

  /*Condition to check first array*/

if(firstLast2(a1, 5))

{

/*Print statement for true block*/

cout<<"The array contains a value 2  either at beginning and end of the array\n";

}

  //Else statement

else{

/*Print statement for false block*/

cout<<"The array does not contains a value 2  either at beginning and end of the array\n";

}

/*Condition to check second array*/

if(firstLast2(a2, 4))

{

/*Print statement for true block*/

cout<<"The array contains a value 2  either at beginning and end of the array\n";

}

//Else statement

else{

/*Print statement for false block*/

cout<<"The array does not contains a value 2  either at beginning and end of the array\n";

}

/*Condition to check third array*/

if(firstLast2(a3, 7))

{

/*Print statement for true block*/

cout<<"The array contains a value 2  either at beginning and end of the array\n";

}

//Else statement

else{

/*Print statement for false block*/

cout<<"The array does not contains a value 2  either at beginning and end of the array\n";

}

/*Condition to check fourth array*/

if(firstLast2(a4, 3))

{

/*Print statement for true block*/

cout<<"The array contains a value 2  either at beginning and end of the array\n";

}

//Else statement

else{

/*Print statement for false block*/

cout<<"The array does not contains a value 2  either at beginning and end of the array\n";

}

}

Sample Output

Output:

The array contains a value 2 either at beginning and end of the array

The array contains a value 2 either at beginning and end of the array

The array does not contains a value 2 either at beginning and end of the array

The array does not contains a value 2 either at beginning and end of the array