out of bounds error
i'm trying to get this code to count down from 60 to 40 and then from 100 to 90.
i attempted to make an empty array, put the appropriate numbers in the array and then put the numbers from the array into an empty string.
but i get an out of bounds error. what do i need to change?
thanks
class CounterSS
{
publicstaticvoid main(String[] args)
{
System.out.println(counter (60, 40, 2) );
//count down from 60 to 40 in twos.
System.out.println(counter (100, 90, 1) );
//count down from 100 to 90 in ones.
}
publicstatic String counter(int z,int x,int c)
{
String countnums ="";
if(z > x){
int s = z - x;
int[] count =newint[s];//create an empty array
int k = 0;
while(k < count.length){
k++;
count[k] = z;
z = z -c;
}
for(int r = 0; r< count.length; r++)
{
countnums = countnums + count[r];
}
}
return countnums;
}
}
java.lang.ArrayIndexOutOfBoundsException: 20
at CounterSS.counter(CounterSS.java:32)
at CounterSS.main(CounterSS.java:8)
Exception in thread "main"
**** JDK Commander: E n do fj a v ae x e c u t i o n****
[2328 byte] By [
mark_8206a] at [2007-11-26 19:58:01]
i suppose i should know this but when counting downwards, all lines miss the last number.
for example, the first line counts down to 42 and not 40.
is the problem with the while or for loop? or maybe both?
class Counter
{
public static void main(String[] args)
{
System.out.println(counter (60, 40, 2) );
//count down from 60 to 40 in twos.
System.out.println(counter (100, 90, 1) );
//count down from 100 to 90 in ones.
System.out.println(counter (100, 80, 10) );
//count down from 100 t0 80 in tens.
}
public static String counter(int z, int x, int c)
{
String countnums = "";
if(z > x) {
int s = z - x; s = s / c;
int[] count = new int[s]; //create an empty array
int k = 0;
while (k < count.length) {
count[k] = z;
z = z -c;
k++;
}
for(int r = 0; r< count.length; r++)
{
countnums = countnums + count[r]+" ";
}
}
return countnums;
}
}
60 58 56 54 52 50 48 46 44 42
100 99 98 97 96 95 94 93 92 91
100 90
**** JDK Commander: E n do fj a v ae x e c u t i o n****
> i suppose i should know this but when counting
> downwards, all lines miss the last number.
> for example, the first line counts down to 42 and not
> 40.
> is the problem with the while or for loop? or maybe
> both?
int s = z - x; s = s / c; // problem here
It's also ugly to put both statements on one line. Either put them on two lines, or combine them:
int s = (z-x)/c; // Still a problem in calculation
Since you are missing exactly one element with your calculation of s, what do you think you need to add to make it correct?
Say z = 5 and x = 1 and c = 1. You know that's 5 numbers. But, your formula for s says:
int s = (5 - 1) / 1 = 4;
Say z = 20 and x = 11 and c = 1. You know that's 10 numbers. But, your formula for s says:
int s = (20 - 11) / 1 = 9;
Does that help?
