double float的精度问题

 #include <iostream>
 #include <stdio.h>
 #include <string.h>

 using namespace std;

 int main()
 {
     double a=0.0001;
     float b=0.1;
     int c=(int)(a*1000)/b;
     cout<<c<<endl;
 }     ///期望c==1   结果c却==0
 #include <iostream>
 #include <