Question

Example 2: In this example we will simply find the factorial of a number which we will request from the user. More explicitly, we want the mini program to ask a number from a user, verify that the number is not negative, and compute its factorial. (15p)

Answer 1

Dear Student,

As the programming language is not mentioned so by default i have written the program in C++ language, if you need the program in any other language, please let me know.

Below i have written the complete C++.

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Program:

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#include<iostream>

using namespace std;

//start of the main function

int main()

{

//variable declration

int num, fact = 1;

//validate that the input number is only positive number

do

{

cout<<"Enter a number: ";

cin>>num;

//if input number is negative throw a warning

if(num<0)

{

cout<<"Invalid input! please enter a positive number."<<endl;

}

}while(num<0);

int buf = num;

//if num is zero then factorial is 1

if(num == 0)

{

fact = 1;

}

//else find the factorial

else

{

while(num>0)

{

fact = fact * num;

num--;

}

}

//display the factorial

cout<<"Factorial of "<<buf<<" is = "<<fact<<endl;

return 0;

}

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Sample Output:

nirmalsharma@ubuntu:~$ g++ fact.cpp nirmalsharma@ubuntu:~$ ./a.out Enter a number: -10 Invalid input! please enter a positive number. Enter a number: -2 Invalid input! please enter a positive number. Enter a number: 5 Factorial of 5 is = 120 nirmalsharma@ubuntu:-$ 1

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Kindly Check and Verify Thanks...!!!