Module: Subroutines: procedures and functions - 2


Problem

6/10

Boolean function

Theory Click to read/hide

Often programmers use boolean functions that return boolean values: true or false (True or False)
Such functions are useful for   check some property.
Consider two examples of writing a logical function that checks a number for evenness

1)  Better way:
expression result
n % 2 == 0
will be true (True) or false (False)
No need to write a conditional statement!		 2) Don't do that!
You can write it like that, but it will turn out to be a longer record, so it’s better not to do it		 
bool isEven(int n)
{
    return (n % 2 == 0);
}

bool isEven(int n)
{
    if (n % 2 == 0)
        return true;
    else
        return False;
}

And the last note about working with functions and procedures: the number of functions and procedures in the program is not limited. In addition, one subroutine can call another subroutine and even itself.
 

Problem

An integer is called prime if it is only divisible by 1 and itself. Write a boolean function (a function that returns true or false) that determines whether a given number is prime.
The main program uses the result of the logic function.

time 1000 ms
memory 256 Mb
Rules for program design and list of errors in automatic problem checking

Teacher commentary

Insert the missing code snippets
Pascal
Write the program below 
#include<iostream>
using namespace std;  
main()
{
 int N;
 cin>>N;
 if (prost(N))
   cout<<"YES";
 else
    cout<<"NO";
}

     

Program check result

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