How to determine whether an integer is even or odd without using if else or switch ?

gaurav.bhorkar · 2009-09-01T01:44:00+00:00

This was the question in Level 1 of the C Programming competition at SRKNEC, Nagpur. Write a program which accepts input as an integer and prints ODD if it is odd and EVEN if its even. (Note: You cannot use if else, switch, loops. Only use printf and scanf) and I couldn't code that. Any Hint from you ?

How to determine whether an integer is even or odd without using if else or switch ?

gaurav.bhorkar

Member

Updated: Oct 26, 2024

Views: 1.0K

This was the question in Level 1 of the C Programming competition at SRKNEC, Nagpur.

Write a program which accepts input as an integer and prints ODD if it is odd and EVEN if its even.
(Note: You cannot use if else, switch, loops. Only use printf and scanf)

and I couldn't code that.

Any Hint from you ?

0

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Kaustubh Katdare

Administrator • Sep 1, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

gaurav.bhorkar
This was the question in Level 1 of the C Programming competition at SRKNEC, Nagpur.

Write a program which accepts input as an integer and prints ODD if it is odd and EVEN if its even.
(Note: You cannot use if else, switch, loops. Only use printf and scanf)

and I couldn't code that.

Any Hint from you ?
This is a simple question. How about trying to write an algorithm? 😀

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sookie

Member • Sep 1, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

Hi Gaurav,

I guess "Ternary operators" are made to use in such cases only. I would have used ternary operators in that case. Following is my program in Java [ Note: NOT IN 'C'. 'C/C++' users can change it using scanf and printf ]

package myjava;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 * @author sookie
 */
public class EvenOrOddTernaryProgram {

    public static void main(String[] args) throws IOException{
        Integer inputNo;
        BufferedReader bin = new BufferedReader(new InputStreamReader(System.in));
        inputNo = Integer.parseInt(bin.readLine());
        System.out.println(inputNo%2==0?"Even number":"Odd number");
    }
}

Output:
12
Even number
567
Odd number

Thanks !

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Sahithi Pallavi

Member • Sep 1, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

I think this is a very simple question..! I used conditional operators to write the program.

#include<stdio.h>
void main()
{
int x;
printf("Enter a number");
scanf("%d",&x);
(x%2==0)?printf("even number"): printf("Odd number");
}

output :-

Enter a number
7
Odd number

--> Enter a number
8
Even number

WINNERS DONT DO DIFFERENT THING..THEY DO THINGS DIFFERENTLY..

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Saandeep Sreerambatla

Member • Sep 1, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

This can be done without using any operators.

#include<stdio.h>
void main()
{
Char Array[0] = "Even";
Char Array[1] = "Odd";
int x;
printf("Enter a number");
scanf("%d",&x);
printf("The number is %s", Array[x%2])
}

This function gives you the number which is even or odd, Please check for syntax errors and array declarations since I didnt compile this .
But the basic idea is 0 location is even and 1 is Odd.
I hope you understood!!

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gaurav.bhorkar

Member • Sep 1, 2009
Re: How to determine whether an integer is even or odd without using if else or switc

@sookie
@sahiti pallavi
We cannot use ternary operators or any decision control instructions in this question.

I think English-Sacred's approach is correct. Maybe we can use an array of pointers to strings instead of two separate arrays. This program works when modified in this way:
```
#include<stdio.h>
void main()
{
     char *arr[] = {
                   "Even",
                   "ODD"
                   };
     int x;
     printf("Enter a number");
     scanf("%d",&x);
     printf("The number is %s", arr[x%2]);
     getch ();
}
```
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Sahithi Pallavi

Member • Sep 2, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

nice work Es..!

WINNERS DONT DO DIFFERENT THING..THEY DO THINGS DIFFERENTLY..

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sookie

Member • Sep 2, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

@Gaurav: Cool man, just one question - in what real life scenarios such kind of programming constraints are put up[like not using decision control instructions] and in what all cases such kind of programming is useful? Why programmers are expected to write a program like this? Why they are taught these if..else, switch..ternary and blah blah things? Any ideas you have? Why such things are not removed from the syllabus?

PS: You can ignore the question if don't have good answers.

Thanks !

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Saandeep Sreerambatla

Member • Sep 2, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

My take for this question Sookie --

The actual scenario in programming is How simple you do the coding , since any program can be done in many ways .
But the simple method is the best one to understand and to work on!!

Well all other logics are said because we have to use them in all other programs.

The simplest way will be the better way to understand anything generally.

Anyway for the above question solving without use of conditional operators is to get the logic.

There is a similar question in the same style, Can you swap the numbers without using third variable .

Anyway we can do it in many ways but the logic is also important .

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enthudrives

Member • Sep 2, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

A great work buddy. Brilliant souls.. 😀

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gaurav.bhorkar

Member • Sep 3, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

Yes, there are different ways to program and the simplest way is the best. The logic is the main part.
Anyways, this was a part of a competition and thats why they asked to code it in such a way. But I learned some good things here. Thank You !

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sookie

Member • Sep 6, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

gaurav.bhorkar
Yes, there are different ways to program and the simplest way is the best. The logic is the main part.
Yeah ! though at times the simplest way is not OPTIMUM. Anyway , thanks a ton 😐

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Tim1

Member • Sep 6, 2009

Re: How to determine whether an integer is even or odd without using if else or switc

Simplest answer in C/C++ to test if unsigned integer variable "x" is odd or even:

isOdd = x & 0x1;
isEven = ! (x & 0x1);

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