let msg:string ='hello world'
console.log('msg:'+msg)

let num:number =15
console.log('num:'+num)

let finished:boolean = true
console.log("finish:"+finished)

let a:any='jack'
a=15
console.log("a"+a)

let p ={name:'jack',age:15}
console.log(p.name)
console.log(p['age'])

let names:Array<string>=['Bob','Luck']
let ages:number[]=[21,18]

console.log(names[1])
console.log(ages[0])