求1-100数字的和

function sum_all(){
  var result = 0;
  for(var i=0;i<=100;i++){
    result=result+i;
  }
  return result;
}
var s = sum_all(100);
console.log(s);

// while循环
function sum_all(){
  var result= 0;
  var i=0;
  while(i<=100){
    i++;
    result=result+i;
  }
  return result;
}
//do while语句
function sum_all(){
  var result = 0;
  var i=0;
  do{
    i++;
    result=result+i;
  }
  while(i<=100){
    return result
  }
}
alert(sum_all())

作者：jser_dimple