% cat sprin
#! /usr/bin/perl -w

use strict;

for( 0..9 ) {
    my $num0 = "1.$_";
    my $num1 = "1.0$_";
    my $num2 = "1.00$_";
    printf "$num0 => %0.0f  $num1 => %0.1f  $num2 => %0.2f\n",
        $num0, $num1, $num2;
}

##</code><code>##

% perl sprin
1.0 => 1  1.00 => 1.0  1.000 => 1.00
1.1 => 1  1.01 => 1.0  1.001 => 1.00
1.2 => 1  1.02 => 1.0  1.002 => 1.00
1.3 => 1  1.03 => 1.0  1.003 => 1.00
1.4 => 1  1.04 => 1.0  1.004 => 1.00
1.5 => 2  1.05 => 1.1  1.005 => 1.00
1.6 => 2  1.06 => 1.1  1.006 => 1.01
1.7 => 2  1.07 => 1.1  1.007 => 1.01
1.8 => 2  1.08 => 1.1  1.008 => 1.01
1.9 => 2  1.09 => 1.1  1.009 => 1.01

##</code><code>##

include <stdlib.h>
#include <stdio.h>

int main( int argc, char **argv ) {
    char *fmt = *++argv;
    double f = atof( *++argv );
    char buf[128];
    sprintf( buf, "%%s => %s\n", fmt );
    printf( buf, *argv, f );
    return 0;
}

##</code><code>##

% ./s %0.0f 0.4
0.4 => 0
% ./s %0.0f 0.5
0.5 => 0
% ./s %0.0f 0.6
0.6 => 1
% ./s %0.0f 1.4
1.4 => 1
% ./s %0.0f 1.5
1.5 => 2
% ./s %0.0f 1.6
1.6 => 2