typeof-->可以查出型别
let a = 1 ; undefined a 1 typeof a "number"
a的型别是"number"
let milkPrice = 30;let milkNum = 5 ;let totle = milkPrice * milkNum ;totle150
总共是150
ex:anita身上有200元,经过清心饮料店,想买饮料给家人喝,一杯无糖少冰乌龙绿茶30元,一杯无糖少冰养乐多绿茶45元,两杯无糖少冰青茶30元,请问anita还剩多少钱?
1.anita身上有200元
2.乌龙绿茶30元
3.养乐多绿茶45元
4.青茶30元
5.乌龙绿茶一杯
6.养乐多绿茶一杯
7.青茶两杯
let anitaMoney = 200 ;let OolongteaPrice = 30 ;let YakultgreenteaPrice = 45 ;let Greenteaprice = 30 ;let OolongteaNum = 1 ;let YakultgreenteaNum = 1 ;let GreenteaNum = 2 ;let leftMoney = anitaMoney-(OolongteaPrice * OolongteaNum)-(YakultgreenteaPrice * YakultgreenteaNum)-(Greenteaprice * GreenteaNum) ;
ans:leftMoney = 65