|
Answer 3 |
Write a program in Java which will parse and recognise (output "Accept") all and only expressions which conform to ONE of the sets of syntax rules designed for the previous question.
This is the program.
//
Written by Steve Edwards 25/05/01
// This needs Hanson's class's to work
import
java.io.*;
class
syntax_date {
public static void main(String param[])throws
Exception{
input
in=new input();
output out=new output();
out.writeln("This program will except or reject a
date input." +"\n"
+"If
the date input is excepted it will write the output. "+"\n"
+"Type
in your date in this format dd/mm/yyyy followed by return."
+"\n");
int day=in.readint();
in.readnext();
// skips the - / or blanks
int month=in.readint();
in.readnext();
int year=in.readint();
out.writeln();
int count = 0; // starts a counter
if
((day<1)|(day>31)){
// rejects days out of range
out.writeln("Days are between 01 and 31," +"\n"
+"your day input is out of range.");
count=1;
}
if ((month<1)|(month>12)){
// rejects months out of range
out.writeln("Month must be in the range 01 to
12." +"\n"
+"your
month input is out of range.");
count=1;
}
if ((year<0)|(year>9999)){
// rejects years out of range
out.writeln("Years are between 0000 and 9999,"+"\n"
+"your year input is out of range.");
count=1;
}
if
((month==4)|(month==6)|(month==9)|(month==11) && day>30){
// rejects month that should have 30 days
out.writeln("There are only 30 days in this
month.");
count=1;
}
else if (month==2){
// starts checking Feb
if (day>29){
// rejects Feb days out of range
out.writeln("February's day range must be in the 01
to 28,"
+"(and
29 in a leap year).");
count=1;
}
if
((day==29 & (year%4!=0 && year%100==0 || year%400!=0)){ //rejects no leap year
29 days
out.writeln("There are only 28 days in February
year " +year);
count=1;
}
}
if (count==0){
// each rejection has a count of 1, unless
count is 0 the input is rejected
if (day < 10 && month >= 10
&& year >=1000){
// tidy up of date printout format
out.writeln("The date 0" +day +"-"
+month +"-" +year +"
is accepted."+"\n");
}
else if (day >= 10 && month < 10
&& year >=1000){
//
tidy up of date printout format
out.writeln("The date " +day +"-0"
+month +"-" +year +"
is accepted."+"\n");
}
else if (day < 10 && month < 10
&& year >=1000){
// tidy up of date printout format
out.writeln("The date 0" +day +"-0"
+month +"-" +year +"
is accepted."+"\n");
}
else if(day >=10 && month >= 10
&& year <100){
// tidy up of date printout format
out.writeln("The date " +day +"-"
+month +"-00" +year +"
is accepted."+"\n");
}
else if(day <10 && month >= 10
&& year <100){
// tidy up of date printout format
out.writeln("The date 0" +day +"-"
+month +"-00" +year +"
is accepted."+"\n");
}
else if(day >=10 && month <
10 && year <100){
// tidy up of date printout format
out.writeln("The date " +day +"-0"
+month +"-00" +year +"
is accepted."+"\n");
}
else if(day <10 && month < 10
&& year <100){
// tidy up of date printout
format
out.writeln("The date 0" +day +"-0"
+month +"-00" +year +"
is accepted."+"\n");
}
else if(day >=10 && month
>= 10 && year <1000){
// tidy up of date printout format
out.writeln("The date " +day +"-"
+month +"-0" +year +"
is accepted."+"\n");
}
else if(day <10 && month >= 10
&& year <1000){
// tidy up of date printout format
out.writeln("The date 0" +day +"-"
+month +"-0" +year +"
is accepted."+"\n");
}
else if(day >=10 && month < 10
&& year <1000){
// tidy up of date printout format
out.writeln("The date " +day +"-0"
+month +"-0" +year +"
is accepted."+"\n");
}
else if(day <10 && month < 10
&& year <1000){
// tidy up of date printout format
out.writeln("The date 0" +day +"-0"
+month +"-0" +year +"
is accepted."+"\n");
}
else if(day >= 10 && month >= 10
&& year >=1000){
// tidy up of date printout format
out.writeln("The date " +day +"-"
+month +"-" +year +"
is accepted."+"\n");
}
}
if (count >=1)
// each rejection has a count of 1, unless
count is 0 the input is rejected
out.writeln("The date you input has not been
accepted"+"\n");
in.close();
out.close();
}
}