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Java Program to keep track of a list of Static IP Addresses
Hello all-
Basically, I have a bunch of static IP addresses. I have an array filled with the last 3 digits of each address (the first 9 numbers are all the same of the address), and I am going to compare that array to another array filled with the numbers 1 --> length (user defines this). Eventually, I hope to store the IP's being used in a text file rather than an array. Anyways, those two arrays are compared and the IP's not already in the original array will be put into a new one.
I know, this is confusing, but please look at the code, its alot simpler. It compiles, but I am getting a buffer overflow. Can anyone offer help? Thanks!
Sorry about the code, I can never get these code boxes to format correctly.
Code:
import java.util.Scanner;
public class Free_IP {
public static void main(String[] args) {
int count_Used = 0; // Keeps track of the # of Used IP Addresses
int count_New = 0; //Keeps track of the # of New IP Addresses
Scanner scan = new Scanner(System.in);
System.out.print("Please enter the maximum # of IP Addresses: ");
int length = scan.nextInt();
//=======================================================================================================================================================
// array_Used holds the last digits of the IP Addresses that are already in use
// array_Sample is an array that holds the numbers 0 --> length, used to compare with array_Used
// array_New is where the IP Addresses not in use will be stored
int[] array_Used = {1,13,14,21,21,21,22,22,22,22,27,28,30,33,38,39,51,52,62,63,73,81,89,99,101,104,124,154,156,189,199,201,213,229,235,251,253};
int[] array_Sample = new int[length];
int[] array_New = new int[length];
//=======================================================================================================================================================
for (int i=0; i<length; i++){ // While i is less than whatever the user specifies,
array_Sample[i] = i; // Set array_Sample[i]=i (Not sure if this works, i want it go initialize
// the array to go from 0,1,2,3,4,...length
}
for (int a = 0; a <= length; a++){ // While a is less than whatever the user specifies,
if (array_Used[a] == array_Sample[a]){ // If the current element in the Used Array = the current element in the Sample array,
count_Used++; // Then just increment count_Used
}
else{ // If the current element in the Used Array is not equal to the current element in the Sample array,
for (int c = 0; c<= length; c++){
array_New[c] = array_Sample[a]; // Then the current element is stored in the New Array
count_New++;
// And count_New is incremented
}
}
}
//=======================================================================================================================================================
// The following outputs the Free IP Addresses, and count_Used as well as count_New
for (int d = 0; d <= array_New.length; d++){
System.out.println("The following IP Addresses are free to use:");
System.out.println("XXX.XXX.XXX." + array_New[d]);
System.out.println("There are " + count_Used + "IP Addresses in use and " + count_New + "IP Addresses that are free.");
}
//=======================================================================================================================================================
}
}
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In the line:
for(int a = 0; a <= length; a++ )
That line is wrong, because array_Sample only has indicies from 0 to length-1.
Hope this helps.
~evlich
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i appreciate the help, and i see what you mean, however i am still getting overflow problems
any more suggestions?
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You have that a lot of places, did you fix them all? Pretty much anyplace that you use <= you should probably be using <. If you are still getting them, can you post the line number that's throwing the exception?
Hope this helps.
~evlich
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In an attempt to "visualize" my program more clearly, I added methods to it...unfortunately, I am still getting an overflow, and I can't see why for the life of me...I did what you said and changed all of the <='s to <'s, but it is still not working...I am getting exceptions at:
line 47: if (array_Used[m] == array_Sample[m]){
and
line 21: Compare_Arrays(array_Used, array_Sample, array_New);
Also, when initializing the arrays, i set the size from length to length+1, this way if the user enters the length as 50, the array contains 0-50 as opposed to 0-49
thanks for all of your help!
Code:
import java.util.Scanner;
public class Free_IP2 {
public static int count_New = 0;
public static int count_Used = 0;
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int[] array_Used = {1,13,14,21,21,21,22,22,22,22,27,28,30,33,38,39,51,52,62,63,73,81,89,99,101,104,124,154,156,189,199,201,213,229,235,251,253};
System.out.print("Please enter the maximum # of IP Addresses " + "[> " + array_Used.length + "]:");
int length = scan.nextInt();
int[] array_Sample = new int[length+1];
int[] array_New = new int[length+1];
Initialize_Array(array_Sample, length);
Compare_Arrays(array_Used, array_Sample, array_New);
for (int d = 0; d < array_New.length; d++){
System.out.println("XXX.XXX.XXX." + array_New[d]);
}
}
public static int[] Initialize_Array(int[] array_Sample, int length){
for (int i=0; i<length+1; i++){
array_Sample[i] = i;
}
return array_Sample;
}
public static int[] Compare_Arrays(int[] array_Used, int[] array_Sample, int[] array_New){
for (int m=0; m<array_Sample.length; m++){
if (array_Used[m] == array_Sample[m]){
Free_IP2.count_Used++;
}
else{
array_New[m] = array_Sample[m];
Free_IP2.count_New++;
}
}
return array_New;
}
}
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Ah, I think I see the problem. You are using the following line of code:
if (array_Used[m] == array_Sample[m])
but what happens when array_Used is smaller then array_Sample?
I think that changing the compare_arrays method as follows would fix it:
Code:
public static int[] Compare_Arrays(int[] array_Used, int[] array_Sample, int[] array_New){
for (int m=0; m<array_Sample.length; m++){
for(int n=0; n<array_Used; n++) {
if (array_Used[n] == array_Sample[m]){
Free_IP2.count_Used++;
}
else{
array_New[m] = array_Sample[m];
Free_IP2.count_New++;
}
}
}
return array_New;
}
What I do here is loop through the Array_Used array once for each item in the ArrayNew array.
Mark
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you're right, that did the job, thanks!
onto the next challenge, however...(there always seems to be more!)
this is the output that i am getting:
Code:
XXX.XXX.XXX.0
XXX.XXX.XXX.1
XXX.XXX.XXX.2
XXX.XXX.XXX.3
XXX.XXX.XXX.4
XXX.XXX.XXX.5
XXX.XXX.XXX.6
XXX.XXX.XXX.7
XXX.XXX.XXX.8
XXX.XXX.XXX.9
XXX.XXX.XXX.10
XXX.XXX.XXX.11
XXX.XXX.XXX.12
XXX.XXX.XXX.13
XXX.XXX.XXX.14
XXX.XXX.XXX.15
XXX.XXX.XXX.16
XXX.XXX.XXX.17
XXX.XXX.XXX.18
XXX.XXX.XXX.19
XXX.XXX.XXX.20
XXX.XXX.XXX.21
XXX.XXX.XXX.22
XXX.XXX.XXX.23
XXX.XXX.XXX.24
XXX.XXX.XXX.25
XXX.XXX.XXX.26
XXX.XXX.XXX.27
XXX.XXX.XXX.28
XXX.XXX.XXX.29
XXX.XXX.XXX.30
XXX.XXX.XXX.31
XXX.XXX.XXX.32
XXX.XXX.XXX.33
XXX.XXX.XXX.34
XXX.XXX.XXX.35
XXX.XXX.XXX.36
XXX.XXX.XXX.37
XXX.XXX.XXX.38
XXX.XXX.XXX.39
XXX.XXX.XXX.40
XXX.XXX.XXX.41
XXX.XXX.XXX.42
XXX.XXX.XXX.43
XXX.XXX.XXX.44
XXX.XXX.XXX.45
XXX.XXX.XXX.46
XXX.XXX.XXX.47
XXX.XXX.XXX.48
XXX.XXX.XXX.49
XXX.XXX.XXX.50
XXX.XXX.XXX.51
XXX.XXX.XXX.52
XXX.XXX.XXX.53
XXX.XXX.XXX.54
XXX.XXX.XXX.55
XXX.XXX.XXX.56
XXX.XXX.XXX.57
XXX.XXX.XXX.58
XXX.XXX.XXX.59
XXX.XXX.XXX.60
XXX.XXX.XXX.61
XXX.XXX.XXX.62
XXX.XXX.XXX.63
XXX.XXX.XXX.64
XXX.XXX.XXX.65
XXX.XXX.XXX.66
XXX.XXX.XXX.67
XXX.XXX.XXX.68
XXX.XXX.XXX.69
XXX.XXX.XXX.70
XXX.XXX.XXX.71
XXX.XXX.XXX.72
XXX.XXX.XXX.73
XXX.XXX.XXX.74
XXX.XXX.XXX.75
XXX.XXX.XXX.76
XXX.XXX.XXX.77
XXX.XXX.XXX.78
XXX.XXX.XXX.79
XXX.XXX.XXX.80
XXX.XXX.XXX.81
XXX.XXX.XXX.82
XXX.XXX.XXX.83
XXX.XXX.XXX.84
XXX.XXX.XXX.85
XXX.XXX.XXX.86
XXX.XXX.XXX.87
XXX.XXX.XXX.88
XXX.XXX.XXX.89
XXX.XXX.XXX.90
XXX.XXX.XXX.91
XXX.XXX.XXX.92
XXX.XXX.XXX.93
XXX.XXX.XXX.94
XXX.XXX.XXX.95
XXX.XXX.XXX.96
XXX.XXX.XXX.97
XXX.XXX.XXX.98
XXX.XXX.XXX.99
XXX.XXX.XXX.100
XXX.XXX.XXX.101
XXX.XXX.XXX.102
XXX.XXX.XXX.103
XXX.XXX.XXX.104
XXX.XXX.XXX.105
XXX.XXX.XXX.106
XXX.XXX.XXX.107
XXX.XXX.XXX.108
XXX.XXX.XXX.109
XXX.XXX.XXX.110
XXX.XXX.XXX.111
XXX.XXX.XXX.112
XXX.XXX.XXX.113
XXX.XXX.XXX.114
XXX.XXX.XXX.115
XXX.XXX.XXX.116
XXX.XXX.XXX.117
XXX.XXX.XXX.118
XXX.XXX.XXX.119
XXX.XXX.XXX.120
XXX.XXX.XXX.121
XXX.XXX.XXX.122
XXX.XXX.XXX.123
XXX.XXX.XXX.124
XXX.XXX.XXX.125
XXX.XXX.XXX.126
XXX.XXX.XXX.127
XXX.XXX.XXX.128
XXX.XXX.XXX.129
XXX.XXX.XXX.130
XXX.XXX.XXX.131
XXX.XXX.XXX.132
XXX.XXX.XXX.133
XXX.XXX.XXX.134
XXX.XXX.XXX.135
XXX.XXX.XXX.136
XXX.XXX.XXX.137
XXX.XXX.XXX.138
XXX.XXX.XXX.139
XXX.XXX.XXX.140
XXX.XXX.XXX.141
XXX.XXX.XXX.142
XXX.XXX.XXX.143
XXX.XXX.XXX.144
XXX.XXX.XXX.145
XXX.XXX.XXX.146
XXX.XXX.XXX.147
XXX.XXX.XXX.148
XXX.XXX.XXX.149
XXX.XXX.XXX.150
XXX.XXX.XXX.151
XXX.XXX.XXX.152
XXX.XXX.XXX.153
XXX.XXX.XXX.154
XXX.XXX.XXX.155
XXX.XXX.XXX.156
XXX.XXX.XXX.157
XXX.XXX.XXX.158
XXX.XXX.XXX.159
XXX.XXX.XXX.160
XXX.XXX.XXX.161
XXX.XXX.XXX.162
XXX.XXX.XXX.163
XXX.XXX.XXX.164
XXX.XXX.XXX.165
XXX.XXX.XXX.166
XXX.XXX.XXX.167
XXX.XXX.XXX.168
XXX.XXX.XXX.169
XXX.XXX.XXX.170
XXX.XXX.XXX.171
XXX.XXX.XXX.172
XXX.XXX.XXX.173
XXX.XXX.XXX.174
XXX.XXX.XXX.175
XXX.XXX.XXX.176
XXX.XXX.XXX.177
XXX.XXX.XXX.178
XXX.XXX.XXX.179
XXX.XXX.XXX.180
XXX.XXX.XXX.181
XXX.XXX.XXX.182
XXX.XXX.XXX.183
XXX.XXX.XXX.184
XXX.XXX.XXX.185
XXX.XXX.XXX.186
XXX.XXX.XXX.187
XXX.XXX.XXX.188
XXX.XXX.XXX.189
XXX.XXX.XXX.190
XXX.XXX.XXX.191
XXX.XXX.XXX.192
XXX.XXX.XXX.193
XXX.XXX.XXX.194
XXX.XXX.XXX.195
XXX.XXX.XXX.196
XXX.XXX.XXX.197
XXX.XXX.XXX.198
XXX.XXX.XXX.199
XXX.XXX.XXX.200
XXX.XXX.XXX.201
XXX.XXX.XXX.202
XXX.XXX.XXX.203
XXX.XXX.XXX.204
XXX.XXX.XXX.205
XXX.XXX.XXX.206
XXX.XXX.XXX.207
XXX.XXX.XXX.208
XXX.XXX.XXX.209
XXX.XXX.XXX.210
XXX.XXX.XXX.211
XXX.XXX.XXX.212
XXX.XXX.XXX.213
XXX.XXX.XXX.214
XXX.XXX.XXX.215
XXX.XXX.XXX.216
XXX.XXX.XXX.217
XXX.XXX.XXX.218
XXX.XXX.XXX.219
XXX.XXX.XXX.220
XXX.XXX.XXX.221
XXX.XXX.XXX.222
XXX.XXX.XXX.223
XXX.XXX.XXX.224
XXX.XXX.XXX.225
XXX.XXX.XXX.226
XXX.XXX.XXX.227
XXX.XXX.XXX.228
XXX.XXX.XXX.229
XXX.XXX.XXX.230
XXX.XXX.XXX.231
XXX.XXX.XXX.232
XXX.XXX.XXX.233
XXX.XXX.XXX.234
XXX.XXX.XXX.235
XXX.XXX.XXX.236
XXX.XXX.XXX.237
XXX.XXX.XXX.238
XXX.XXX.XXX.239
XXX.XXX.XXX.240
XXX.XXX.XXX.241
XXX.XXX.XXX.242
XXX.XXX.XXX.243
XXX.XXX.XXX.244
XXX.XXX.XXX.245
XXX.XXX.XXX.246
XXX.XXX.XXX.247
XXX.XXX.XXX.248
XXX.XXX.XXX.249
XXX.XXX.XXX.250
XXX.XXX.XXX.251
XXX.XXX.XXX.252
XXX.XXX.XXX.253
XXX.XXX.XXX.254
XXX.XXX.XXX.255
There are 37 addresses in use and 9435 addresses available.
So, first of all, the outputted number of addresses in use (37) is correct, but the addresses available is waaay to high, it should be 255-37 (=218). Also, as you see, when array_New is being printed, it seems to be a duplicate of array_Sample, it doesn't filter out any of the addresses in use (those in array_Used)
Any suggestions? It's almost as if, in the Compare_Arrays method, the first condition is being ignored all together, and the else statement is running no matter what, but that can't be because count_Used (number of addresses in use) is being outputted with the correct number.
Thanks!
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please help!
if anybody has any suggestions, please help me out...i've been stuck on this for weeks now, and I cannot figure out why it isnt working, it all looks right to me...
thanks!
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i guess it would be useful if i provided the code, sorry!
Code:
import java.util.*;
public class Free_IP2 {
public static int count_New = 0;
public static int count_Used = 0;
public static void main(String[] args) {
int[] array_Used = {1,13,14,21,21,21,22,22,22,22,27,28,30,33,38,39,51,52,62,63,73,81,89,99,101,104,124,154,156,189,199,201,213,229,235,251,253};
int length = 255;
int[] array_Sample = new int[length+1];
int[] array_New = new int[length+1];
Initialize_Array(array_Sample, length);
Compare_Arrays(array_Used, array_Sample, array_New);
for (int d = 0; d < array_New.length; d++){
System.out.println("XXX.XXX.XXX." + array_New[d]);
}
System.out.println("");
System.out.println("There are " + Free_IP2.count_Used + " addresses in use and " + Free_IP2.count_New + " addresses available.");
}
public static int[] Initialize_Array(int[] array_Sample, int length){
for (int i=0; i<length+1; i++){
array_Sample[i] = i;
}
return array_Sample;
}
public static int[] Compare_Arrays(int[] array_Used, int[] array_Sample, int[] array_New){
for (int m=0; m<array_Sample.length; m++){
for(int n=0; n<array_Used.length; n++) {
if (array_Used[n] == array_Sample[m]){
Free_IP2.count_Used++;
}
else{
array_New[m] = array_Sample[m];
Free_IP2.count_New++;
}
}
}
return array_New;
}
}
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