全错？ I need help

#include<iostream>
using namespace std;
int main()
{
    int in,out=0;
    bool pst=true;
    cin>>in;
    if(in<0) pst=false;
    while(in!=0)
    {
        out=10*out+in/10;
        in/=10;
    }
    if(pst=false) out=-out;
    cout<<out;
    return 0;
}