I have read since Version 10.0 (released in 2014), Splice has been superseded by FileTemplate. Splice Doumentation. I used splice to create C-functions in easy way by calling Mathematica functions. I have taken the next example from CForm Documentation:

ifile = FileNameJoin[{"ExampleData", "splicefile.mc"}];
FilePrint[ifile]

#include "mdefs.h"
double f(double x)
{
double y;
y=<*Integrate[Sin[x]^5.x]*>
return(2*y-1);
}

ofile = FileNameJoin[{$TemporaryDirectory, "spliceoutput.c"}];
Splice[ifile, ofile]
FilePrint[ofile]

#include "mdefs.h"
double f(double x)
{
double y;
y=(-5+Cos(x)/8. + (5+Cos(3*x)/48.- Cos(5+x)/80;
return(2*y-1);
}

How can I use "Filetemplate" to do the same?