CODEWITHSUNDEEP
javascriptarraystypeerror
Rohan Nagmoti
Rohan Nagmoti

Reputation: 31

Array is not being passed as argument in javascript.(TypeError:cannot read property 'length' of undefined)

I have a function that should take an (n*n) grid as an argument and output the maximum product of 4 nos. of all rows. (A part of project Euler problem 11). When I try to run the code it gives me,

TypeError: Cannot read property 'length' of undefined

What am I doing wrong here? (I am a beginner so plz tell me if I have any silly mistakes.)

Here is my code:

const grid = [
  [40, 17, 81, 18, 57],
  [74, 4, 36, 16, 29],
  [36, 42, 69, 73, 45],
  [51, 54, 69, 16, 92],
  [7, 97, 57, 32, 16]
];

function largestGridProduct(arr) {
  let product = 1 , maxProduct = 1;
  for(let i=0 ; i<arr.length ; i++){
    for(let j=0 ; j<arr.length-3 ; j++){
      product = grid[i][j] * grid[i][j+1] * grid[i][j+2] * grid[i][j+3];
      if(product > maxProduct){
        maxProduct = product;
      }
    }
  }
  return maxProduct;
}

console.log(largestGridProduct(grid));

So what am i doing wrong here ?

Upvotes: 0

Views: 64

Answers (3)

Žygimantas Pusvaškis
Žygimantas Pusvaškis

Reputation: 17

working like this :)

   if(product > maxProduct){
         return  product = maxProduct;
      }
      return  maxProduct;
    }
  }
}

Upvotes: 0

Rohan Nagmoti
Rohan Nagmoti

Reputation: 31

It was a silly mistake I was using variable name 'grid' instead of 'arr' inside the function. BTW thanks everyone. Ok.Here is my working code :-

const grid = [
  [40, 17, 81, 18, 57],
  [74, 4, 36, 16, 29],
  [36, 42, 69, 73, 45],
  [51, 54, 69, 16, 92],
  [7, 97, 57, 32, 16]
];

function largestGridProduct(arr) {
  let product = 1 , maxProduct = 1;
  for(let i=0 ; i<arr.length ; i++){
    for(let j=0 ; j<arr.length-3 ; j++){
      product = arr[i][j] * arr[i][j+1] * arr[i][j+2] * arr[i][j+3];
      if(product > maxProduct){
        maxProduct = product;
      }
    }
  }
  return maxProduct;
}

console.log(largestGridProduct(grid));

Upvotes: 0

Christian
Christian

Reputation: 7429

You're not returning anything in the function...

By the way, you can make it easier.

See this:

[
  [40, 17, 81, 18, 57],
  [74, 4, 36, 16, 29],
  [36, 42, 69, 73, 45],
  [51, 54, 69, 16, 92],
  [7, 97, 57, 32, 16]
 ].reduce((max, a2) => {
  const val = a2.reduce((a, b) => {
   return Math.max(a, b);
 });
 return Math.max(val, max); 
}, 0)

It's using arrow functions (es6) and array reduce. This returns the max of all the input arrays.

Upvotes: 2

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