PHP Program - Check whether a Number is Even or Odd


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A number is known as an even number if it is a natural number and divisible by $$2$$. On the other hand, an odd number is a natural number which not divisible by $$2$$. Examples:

  • Even Number: $$-10, -4, 0, 6, 18, 50$$
  • Odd Number: $$-11, -5, -1, 9, 21, 99$$

Example: Using conditional statements

In the below example, the number called MyNum is checked for even number by dividing it by $$2$$ and checking the remainder. For even number, the remainder is $$0$$ and for odd number, the remainder is $$1$$.

#include <iostream>
using namespace std;

int main() {
  int MyNum = 17;
  if (MyNum % 2 == 0){
    cout<<MyNum<<" is an even number.";
  } else if (MyNum % 2 == 1) {
    cout<<MyNum<<" is an odd number.";
  }
  return 0;
}

Output

17 is an odd number.

Example: Using function

In the below example, a function called CheckEven() is created which takes a number as argument and checks it for even number.

#include <iostream>
using namespace std;

static void CheckEven(int);

static void CheckEven(int MyNum){
  if (MyNum % 2 == 0){
    cout<<MyNum<<" is an even number.";
  } else if (MyNum % 2 == 1) {
    cout<<MyNum<<" is an odd number.";
  }
}

int main() {
  CheckEven(42);
  return 0;
}

Output

42 is an even number.

Example: Using bitwise operators

When bitwise operator is used, the last bit of the given number is checked. If the last bit is $$1$$, the number will be odd and if the last bit is $$0$$, the number will be even.

Even Number:  50 ->    110010
                     & 000001
                     ---------
                       000000

Odd Number:   99 ->   1100011
                    & 0000001
                     ---------
                      0000001

#include <iostream>
using namespace std;

static void CheckEven(int);

static void CheckEven(int MyNum){
  if ((MyNum & 1) == 1){
    cout<<MyNum<<" is an odd number.\n";
  } else {
    cout<<MyNum<<" is an even number.\n";
  }
}

int main() {
  CheckEven(50);
  CheckEven(99);
  return 0;
}

Output

50 is an even number.
99 is an odd number.




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