代码使用三元运算符，但不能使用if else语句

Question

This javascript program works with ternary operator as expected but not with if else statements. What I am doing wrong?

I am trying to solve some basic javascript exercises but I am stuck at this question. https://www.w3resource.com/javascript-exercises/javascript-basic-exercise-74.php

//Working code with ternary operator
    function all_max(nums) {
      var max_val = nums[0] > nums[2] ? nums[0] : nums[2];

      nums[0] = max_val;
      nums[1] = max_val;
      nums[2] = max_val;

      return nums;
      }
    console.log(all_max([20, 30, 40]));
    console.log(all_max([-7, -9, 0]));
    console.log(all_max([12, 10, 3]));

// With if-else statement

  function all_max(nums) {
     if (var max_val = nums[0] > nums[2]) {
     return nums[0];
    } else {
     return nums[2];
  }

     nums[0] = max_value ;
     nums[1] = max_value ;
     nums[2] = max_value ;

return nums;
}
console.log(all_max([20, 30, 40]));
console.log(all_max([-7, -9, 0]));
console.log(all_max([12, 10, 3]));

Answer 1

You should be assigning the value in the body of the if/else statement, not within the comparison, so something like this should work for you:

 function all_max(nums) { let max_val = 0 if (nums[0] > nums[2]) { max_val = nums[0]; } else { max_val = nums[2]; } nums[0] = max_val; nums[1] = max_val; nums[2] = max_val; return nums; } console.log(all_max([20, 30, 40])); console.log(all_max([-7, -9, 0])); console.log(all_max([12, 10, 3])); 

Answer 2

Below code works

      function all_max(nums) {
let max_val = nums[0] > nums[2]
     if (max_val) {
     return nums[0];
    } else {
     return nums[2];
  }

     nums[0] = max_value ;
     nums[1] = max_value ;
     nums[2] = max_value ;

return nums;
}
console.log(all_max([20, 30, 40]));
console.log(all_max([-7, -9, 0]));
console.log(all_max([12, 10, 3]));

calculate max_val outside if condition and put result in if condition let max_val = nums[0] > nums[2]

Answer 3

Variable declaration within if statement not allowed. Remove it.

Try this if you want only max value

  function all_max(nums) { if (nums[0] > nums[2]) { max_value = nums[0]; } else { max_value = nums[2]; } return max_value; } console.log(all_max([20, 30, 40])); console.log(all_max([-7, -9, 0])); console.log(all_max([12, 10, 3])); 

if you want all the elements in the array to be set to max value, then use this

 function all_max(nums) { if (nums[0] > nums[2]) { max_value = nums[0]; } else { max_value = nums[2]; } nums[0] = max_value; nums[1] = max_value; nums[2] = max_value; return nums; } console.log(all_max([20, 30, 40])); console.log(all_max([-7, -9, 0])); console.log(all_max([12, 10, 3]));