--- loncom/homework/default_homework.lcpm	2001/01/24 17:01:49	1.16
+++ loncom/homework/default_homework.lcpm	2001/05/25 21:20:19	1.20
@@ -3,6 +3,12 @@
 # 
 #
 #init some globals
+#use Math::Trig;
+#
+# Guy Albertelli
+#
+# 05/25/2001 H. K. Ng
+#
 $RANDOMINIT=0;
 $pi=atan2(1,1)*4;
 
@@ -11,11 +17,11 @@ sub caparesponse_check {
   my $type='';    #done
   my $tol_type=''; # gets it's value from whether tol has a % or not done
   my $tol='';     #done
-  my $sig='';
-  my $sig_lbound='';
-  my $sig_ubound='';
+  my $sig='';     #done lowerbnd,upperbnd
+  my $sig_lbound=''; #done
+  my $sig_ubound=''; #done
   my $ans_fmt='';
-  my $units='';
+  my $units='';     #done
   my $calc='';
   my ($response,$expr)=@_;
   
@@ -71,7 +77,7 @@ sub caparesponse_check {
   elsif ($result =='12') { $result='WANTED_NUMERIC'; }
   else  {$result = "ERROR: Unknown Result:$result:$@:";}
 
-  return "$result:<br>Error $error:<br>Answer $answer:<br>Response $response:<br>$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$units<br>";
+  return "$result:<br />Error $error:<br />Answer $answer:<br />Response $response:<br />$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$units<br />";
 }
 
 sub caparesponse_check_list {
@@ -83,24 +89,29 @@ sub caparesponse_check_list {
   my (@list) = eval $answer;
   my (@responselist)=split /,/,$response;
   my $unit='';
-  $result.="Final response :$responselist['-1']:<br>";
+  $result.="Final response :$responselist['-1']:<br />";
   if ( $responselist['-1']=~ /(.*[^\s])\s+([^\s]+)/ ) {
     $responselist['-1']=$1;
     $unit=$2;
   }
-  $result.="Final response :$responselist['-1']:<br>";
+  $result.="Final response :$responselist['-1']:<br />";
   $unit=~s/\s//;
   my $i=0;
   my $awards='';
   for ($i=0; $i<@list;$i++) {
-    $aresult=&caparesponse_check($responselist[$i]." $unit",
-				 $expr.';my $answer='.$list[$i].';');
+    if ($unit eq '') {
+      $aresult=&caparesponse_check($responselist[$i],
+			     $expr.';my $answer='.$list[$i].';');
+    } else {
+      $aresult=&caparesponse_check($responselist[$i]." $unit",
+				   $expr.';my $answer='.$list[$i].';');
+    }
     my ($temp)=split /:/, $aresult;
     $awards.="$temp,";
     $result.=$aresult;
   }
   chop $awards;
-  return "$awards:<br>$result";
+  return "$awards:<br />$result";
 }
 
 sub tex {
@@ -140,8 +151,35 @@ sub random {
 }
 
 sub tan  { sin($_[0]) / cos($_[0]) }
+sub atan { atan2($_[0], 1); }
 sub acos { atan2(sqrt(1 - $_[0] * $_[0]), $_[0] ); }
 sub asin { atan2($_[0], sqrt(1- $_[0] * $_[0]) );  }
+sub log10 { log($_[0])/log(10); }
+sub factorial {
+    my $input = int(shift);
+    return "Error - unable to take factorial of an negative number ($input)" if $input < 0;
+    return "Error - factorial result is greater than system limit ($input)" if $input > 170;
+    return 1 if $input == 0;
+    my $result = 1; 
+    for (my $i=2; $i<=$input; $i++) { $result *= $i }
+    return $result;
+}
+
+sub sgn {
+    return -1 if $_[0] < 0;
+    return 0 if $_[0] == 0;
+    return 1 if $_[0] > 0;
+}
+
+sub min {
+    my @sorted = sort { $a <=> $b || $a cmp $b } @_;
+    return shift @sorted;
+}
+
+sub max {
+    my @sorted = sort { $a <=> $b || $a cmp $b } @_;
+    return pop @sorted;
+}
 
 sub html {
   if ( $external::target eq "web" ) {
@@ -149,6 +187,21 @@ sub html {
   }
 }
 
+sub roundto {
+    my ($input,$n) = @_;
+    return sprintf('%.'.$n.'f',$input);
+}
+
+sub to_string {
+    my ($input,$n) = @_;
+    return sprintf('%'.$n,$input) if $n ne "";
+    return sprintf($input) if $n eq "";
+}
+
+sub sub_string {
+    my ($str,$start,$len) = @_;
+    return substr($str,$start-1,$len);
+}
 
 sub pow   {return $_[0] ** $_[1]; }
 sub ceil  {return (($_[0]-int($_[0]))== 0.0) ? $_[0] : (int($_[0])+ 1); }