# include & ltiostream & gt

# include & ltiomanip & gt// The header file that must be included in the precision setting.

usingnamespacestd

intmain()

{

doublea = 3.5

intb = 10；

//Method 1: Format control of operator functions

//cout.precision(2), and the setting accuracy is 2.

//right: Set left alignment; Fixed: controls the floating-point output format;

//setw(5): Set the output bit width to 5.

Cout & lt& lt Right & lt& lt has been repaired & lt< setw (5) < & ltset fill(“0”)

& lt< setprecision (2)<A<< endl//The output result is 03.50.

//Method 2: Format control of IOS class member functions

cout . precision(4)； //setprecision(4), and the setting precision is 4.

The output of cout & lt& lta<& ltendl// is 3.5000.

//setfill('0'): Set the fill character to' 0'

//static _ cast & lt； Double & gt(b): integer b,

//Generate a double-precision floating-point copy for operation without changing its value and type.

Cout & lt& lt has fixed & lt< Setfill ('0') < < setting accuracy (2)

& lt& lt fixed & lt& lt static _ cast & lt double & gt (b) < & ltendl// output 10.00

return0

}