How to find the sum of an array of numbers

Question

I am having difficulty in finding out the sum of an array in Javascript. Can someone help me with the code and explanation?

Answer 1

There are n numbers of ways to find the sum of array in Java some of them are mentioned below: 

• Method 1 : Using built-in reduce() 

Example: 

function all(arr) { 

  if(!Array.isArray(arr)) return; 

  return arr.reduce((a, v)=>a + v); 

} 

• Using for loop 

Example: 

function all(arr) { 

  if(!Array.isArray(arr)) return; 

  let totalNumber = 0; 

  for (let i=0,l=arr.length; i<l; i++) { 

     totalNumber+=arr[i]; 

  } 

  return totalNumber; 

} 

• Using while loop 

Example: 

function all(arr) { 

  if(!Array.isArray(arr)) return; 

  let allnum = 0, i=-1; 

  while (++i < arr.length) { 

     allnum+=arr[i]; 

  } 

  return allnum; 

}