CODEWITHSUNDEEP
javascript
hui
hui

Reputation: 601

how to use arguments object by js

today,i want to get a sum number,but get a wrong number.

function fun(a,b,c){
  var l = arguments.length;
  console.log('length'+l);
  for(var i=0;i<l;i++){
    var sum;
    console.log(arguments[i]);
    sum= sum+arguments[i];
  }
  return sum;
}
var p= fun(1,2,3);
console.log(p);

p is 'NaN'

if change the fun(1,2,3) to fun(1,2,3,4,5),is there some differences?

Upvotes: 0

Views: 50

Answers (1)

Denys S&#233;guret
Denys S&#233;guret

Reputation: 382102

The problem is you're not initializing sum, so you're adding to undefined the first time (undefined+1 gives NaN), then to NaN.

Change

for(var i=0;i<l;i++){
 var sum;
 console.log(arguments[i]);
 sum= sum+arguments[i];
}

to

var sum = 0;
for(var i=0;i<l;i++){
 console.log(arguments[i]);
 sum= sum+arguments[i];
}

Note that the var sum declaration is hoisted to the start of the function.

Upvotes: 4

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