C + + Set output precision

The precision of the float type is 6-7 bits, the variable of type double is 15-16 bits, but float occupies four bytes, double is eight bytes,

But you can use the float type not double because the double takes up more bytes, and the operation is much slower

Setprecision can set the output bit number, Iomanip is its header file,

#include <iostream><iomanip>usingnamespace  std; int Main () {    double12.345678901234;     << setprecision (+) << A;     return 0 ;}

C + + Set output precision