How to Control Floating-Point Precision in C ostream Output?

Maintaining Floating-Point Precision in Ostream Output

In C , the utilization of "<<" within ostream operations can sometimes result in the display of double values in scientific notation. This can be undesirable in certain scenarios, especially when precision is crucial.

To resolve this issue, the setprecision(n), showpoint, and fixed manipulators can be employed in conjunction to control the formatting of floating-point variables:

setprecision(n)

This restricts the displayed precision of floating-point values to "n" decimal places. Once set, this precision remains in effect until explicitly modified.

fixed

Ensures that all floating-point numbers follow the same display format. With a precision of 4 places, both 6.2 and 6.20 would display as "6.2000".

showpoint

Forces the display of decimal portions for floating-point variables, even if not explicitly included. For example, 4 would be displayed as "4.0".

By combining these manipulators, precise control over floating-point output can be achieved:

#include 

outfile << fixed << showpoint;
outfile << setprecision(4);
outfile << x;

In this example, the precision of the floating-point variable "x" is set to 4 decimal places. The output will always be displayed in fixed notation, with the decimal point present even for integer values.
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