Output decimal Format control in C + + (how to control the number of digits in C + + that are exported after a floating-point decimal point)

First you need to have #include<iomanip> this header file because it is the input output stream format control

Second such as Double sum=10; Cout<<setiosflags (ios::fixed) <<setprecision (1) <<sum;

where Setiosflags (ios::fixed) do not write wrong it with the back of the Setprecision (1) used to control the output decimal point after the number of digits, that is, a bit 10.0;

If only setprecision (1) represents a decimal 1e+001 with a valid number;

cout<< setiosflags (ios::fixed) << setprecision (2) << setiosflags (ios::left) << SETW (+) < < string<< ' a ';//left-aligned, then output the character ' a ' after starting at the 40th position of the string's first letter. In addition the control decimal place is two bits.