Conditionals and loop

pragma solidity ^0.5.13;

contract conditional {
    
      uint public age;
      
      uint[] public arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
      
      
      
      function count_even_no() public view returns(uint) {
          
             uint count = 0;
             
             for(uint i=0; i<arr.length; i++)
            {
                if(arr[i] %2 ==0)
                   count += 1;
            }
            
            return count;
              
             
      }
     
     
      function setvalue(uint _value) public {
          
            age = _value;
        
      }
      
      function checkvalue() public view returns(uint) {
          
            if(age > 10)
             return 1;
            
            else
             return 0;
             
      }
      
      function even_no(uint _no) public pure returns(bool) {
          
            if(_no % 2 == 0)
             return true;
            
            else
             return false;
      }
}