计算器(二)

package main
import _"fmt"
import "strconv"

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param s string字符串 
 * @return int整型
*/
func calculate( s string ) int {
    ints:=[]int{}
    symbols:=[]byte{}
    pre:=""
    for _,ch:=range []byte(s){
        if ch=='-'||ch=='+'{
            ints=append(ints,calc(pre))
            symbols=append(symbols,ch)
            pre=""
        }else{
            pre+=string(ch)
        }
    }
    ints=append(ints,calc(pre))
    ans:=ints[0]
    for i,x:=range ints[1:]{
        if symbols[i]=='-'{
            ans-=x
        }else{
            ans+=x
        }
    }
    return ans
}

func calc(s string)int{
    ints:=[]int{}
    symbols:=[]byte{}
    pre:=""
    for _,ch:=range []byte(s){
        if ch=='*'||ch=='/'{
            x,_:=strconv.Atoi(pre)
            ints=append(ints,x)
            symbols=append(symbols,ch)
            pre=""
        }else{
            pre+=string(ch)
        }
    }
    x,_:=strconv.Atoi(pre)
    ints=append(ints,x)
    ans:=ints[0]
    for i,x:=range ints[1:]{
        if symbols[i]=='*'{
            ans*=x
        }else{
            ans/=x
        }
    }
    return ans
}