#include <iomanip.h>
#include <iomanip>
int main()
{
double num1 = 3.12345678;
cout << fixed << showpoint;
cout << setprecision(2);
cout << num1 << endl;
}
#include <iostream>
int main()
{
std::cout << std::setprecision(n); //to n SIG FIG
// any cout comand will be to n sig fig after this comand
}