/ *
* This program is free software : you can redistribute it and / or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation , either version 3 of the License , or
* ( at your option ) any later version .
*
* This program is distributed in the hope that it will be useful ,
* but WITHOUT ANY WARRANTY ; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE . See the
* GNU General Public License for more details .
*
* You should have received a copy of the GNU General Public License
* along with this program . If not , see < http : //www.gnu.org/licenses/>.
* /
function addChar ( input , character ) {
if ( input . value == null || input . value == "0" )
input . value = character
else
input . value += character
}
function cos ( form ) {
form . display . value = Math . cos ( form . display . value ) ;
}
function sin ( form ) {
form . display . value = Math . sin ( form . display . value ) ;
}
function tan ( form ) {
form . display . value = Math . tan ( form . display . value ) ;
}
function sqrt ( form ) {
form . display . value = Math . sqrt ( form . display . value ) ;
}
function ln ( form ) {
form . display . value = Math . log ( form . display . value ) ;
}
function exp ( form ) {
form . display . value = Math . exp ( form . display . value ) ;
}
function deleteChar ( input ) {
input . value = input . value . substring ( 0 , input . value . length - 1 )
}
function changeSign ( input ) {
if ( input . value . substring ( 0 , 1 ) == "-" )
input . value = input . value . substring ( 1 , input . value . length )
else
input . value = "-" + input . value
}
function square ( form ) {
form . display . value = eval ( form . display . value ) * eval ( form . display . value )
}
function checkNum ( str ) {
for ( var i = 0 ; i < str . length ; i ++ ) {
var ch = str . substring ( i , i + 1 )
if ( ch < "0" || ch > "9" ) {
if ( ch != "/" && ch != "*" && ch != "+" && ch != "-" && ch != "."
&& ch != "(" && ch != ")" ) {
$ ( "#display" ) . text ( "ERROR" ) ;
return false
}
}
}
return true
}