function sum(){
var sum=0;
for (var i = 0; i < arguments.length; i++) {
sum=sum+arguments[i];
}
return sum
}
var val=sum(1,2,3);
console.log('val',val);
function rest(...restNum){
var sum=0;
for (var i = 0; i < restNum.length; i++) {
sum=sum+restNum[i];
}
return sum
}
var valrest=rest(1,2,3);
console.log('valrest',valrest);