在JavaScript中的另一个函数内调用一个函数

Question

I have defined a function named larger to find the larger number between two arguments (num1, num2). Now I want to use this function inside another function called "largest" which gets an array and return the largest number of that array, but I`ve got stuck. Can anybody help me with that? Here is my codes:

function larger(num1, num2){
  var largerNumber = 0;
  if (num1 > num2){
   largerNumber = num1;
  } else {
      largerNumber = num2;
  }
return largerNumber;
}

function largest(array){
 for (var i = 0; i < array.length ; i++){
  for (var j = 0; j < array.length ; j++){
   if (array[i] != array[j]){
     //I don`t know if I am doing it right
   }
  }
 }
}

Answer 1

Just use Math.max :

 function largest(array) { return Math.max.apply(Math, array); } console.log(largest([5,-2,7,6])); 

If you really want to use a custom binary larger function, consider [].reduce :

 function larger(num1, num2) { return num1 > num2 ? num1 : num2; } function largest(array) { return array.reduce(larger, -Infinity); } console.log(largest([5,-2,7,6])); 

Answer 2

The simpliest solution is tu use a max tmp value. This way, you only need to do one iteration over all your array.

function largest(array){
    var max = array[0];
    for (var i = 1; i < array.length ; i++) { // So we start at 1
        max = larger(max, array[i]);
        // Or use this : if(array[i] > max) max = array[i];
    }

AS SAID BY ORIOL

I didn't check the length of the array, the above solution work only if the array.length > 0.

Otherwise, you'll have to check it usingsomething like this instead of var max = array[0];

function largest(array){
    var max = -Infinity; 
    for (var i = 0; i < array.length ; i++) { Start at 0
        max = larger(max, array[i]);
}    

It really depends on the ergonomics of your IHM.

Answer 3

Iterate through the array once, keeping only the largest:

 function larger(num1, num2){ var largerNumber = 0; if (num1 > num2){ largerNumber = num1; } else { largerNumber = num2; } return largerNumber; } function largest(array){ let largestNumber = array[0]; for (var i = 1; i < array.length ; i++){ largestNumber = larger(largestNumber, array[i]); } return largestNumber; } var test = [1, 53, 352, 22, 351, 333, 123, 5, 25, 96]; console.log(largest(test)); 

Answer 4

If you are just trying to find the maximal value, you should go with Oriol's answer: Math.max

If you are looking for a way to call one function from another you can do it like this:

function first_function() {
  //code of first function

  //call to the other function
  second_function();
}

function second_function() {
  //code of second function
}

Answer 5

Set the first element of array to a variable, if next element in array is greater set variable to that element; continue process, return variable

 function largest(array) { if (!array.length) return; for (var i = 0, curr = void 0; i < array.length ; i++) { if (curr === void 0) curr = array[i]; else if (curr < array[i]) curr = array[i]; } return curr } console.log(largest([2,20,2000,2,7]));