中缀表达式转后缀表达式

//"6 9 + 5 3 * - 8 -"

#include <bits/stdc++.h>

using namespace std;

int n,i = 0,a[100];

char a1;

int main(){

    cin>>n;

    while(n--){

        cin>>a1;

        if(a1>='1' && a1<='9'){

            a[++i] = a1-'0';

        }else{

            int x,y,num = 0;

            y = a[i--];

            x = a[i--];

            if(a1=='+'){

                num = x+y;

            }else if(a1=='-'){

                num = x-y;

            }else if(a1=='/'){

                num = x/y;

            }else{

                num = x*y;

            }

            a[++i] = num;

        }

    }

    cout<<a[i];

    return 0;

}