Convert a double to fixed decimal point in C++

Question

I have a double variable in C++ and want to print it out to the screen as a fixed decimal point number.

Basically I want to know how to write a function that takes a

Answer 1

Look at the setprecision manipulator which should give you the idea

Answer 2

#include <iomanip>
#include <iostream.h>

// print a float, x places of precision 
void convert (double number, int x)
{
    cout << setprecision(x) << number << endl;
}

int main()
{
    double a = 1.234;
    convert (a,2);
} 

output: 1.23

reference

Answer 3

Assuming I'm remembering my format strings correctly,

printf("%.*f", (int)precision, (double)number);

Answer 4

There is no such thing as a "fixed decimal place" number. The convert function will need to be the function that actually prints it out. I would suggest getting the whole part of the number, then print it. If [decimal places]>0 then print a decimal place, then print each decimal individually like: floor((n*log(10,d))%10); <-- just an idea, not actual code.