#include <iostream>
#include <iomanip>
 
int main() {
    long long int i=10000000000000;
    float f=100000000000000.0;
 
    auto x = i*f;   // does not account for expected change of scale
    std::cout <<"Type "<< typeid(x).name() <<": "
       <<std::fixed <<std::setw(30)  << x  << std::endl;
 
    long double y = i*(long double)f; // without casting, same as before  
    std::cout <<"Type "<< typeid(y).name() <<": "
       <<std::fixed <<std::setw(30)   <<y  << std::endl;
       // remaining rounding error is because of the initial float.  
       // Correcting the original variable with long double and using auto gives better result !!!
}

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