Solved

# Java arrays and calculations

Posted on 2009-05-18
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I am trying to prompt the user to enter 26 integers(scores) and I want the integers to fall into the specefic category based on the  score the user entered. I want the user to be prompt to enter an integer 26 times. For example If  6 of the 26 scores falls in  the range1 category I would like the counter to be 6. For some reason when i ran it I got the wrong output data.
1 Student has a range below 24
0 Students have a range between 25-49
0 Students have a range between 50-74
and so on with the rest of all the values being 0
Whats wrong with my code?
``````import java.io.*;

import java.util.*;

public class myArray

{

static Scanner console = new Scanner(System.in);

public static void main(String[] args)

{

int[] item = new int[26];

int range1=0, range2=0, range3=0, range4=0, range5=0, range6=0, range7=0,range8=0;

int index;

System.out.println("Enter 26 numbers");

for (index =0; index < item.length; index++)

item[index] = console.nextInt();

if (item.length <=24)

range1++;

else if (item.length >= 25  && item.length <=49)

{

range2++;

}

else if (item.length >= 50 && item.length <=74)

{

range3++;

}

else if(item.length >= 75 && item.length <=99)

{

range4++;

}

else if(item.length >= 100 && item.length <=124)

{

range5++;

}

else if(item.length >= 125 && item.length <=149)

{

range6++;

}

else if(item.length >= 150 && item.length <=174)

{

range7++;

}

else if(item.length >= 175 && item.length <=200)

{

range8++;

}

System.out.println( range1 + "Students have scores that range in the  24 and below category");

System.out.println( range2 + "Students have scores that range between 25 and 49");

System.out.println( range3 + "Students have scores that range between 50 and 74");

System.out.println( range4 + "Students have scores that range between 75 and 99");

System.out.println( range5 + "Students have scores that range between 100 and 124");

System.out.println( range6 + "Students have scores that range between 125 and 149");

System.out.println( range7 + "Students have scores that range between 150 and 174");

System.out.println( range8 + "Students have scores that range between 175 and 200");

}

}
``````
0
Question by:Valisha
• 5
• 3
• 2
• +3

LVL 92

Expert Comment

ID: 24417963
>                 if (item.length <=24)

you are comparing the wrong value, should be:

if (item[index] <=24)

same for all the other comparisons

0

Expert Comment

ID: 24417969
Hi,

you seem to mixing your lengths and elements, item.length, if I remember correctly returns the number of elements in an array, you probably want to change all your tests to something like (for example)

else if (item[index] >= 50 && item[index] <=74)

Cheers

0

Author Comment

ID: 24418048
Hi again when I ran the program this time. I got in error message in the command window that says Exception thread "main" java.lang.ArrayIndexOutofboundsException: 26.
press any key to continue

The println output didn't even display.
0

Expert Comment

ID: 24418058
0

LVL 92

Expert Comment

ID: 24418062
make sure you aren't incrementing index inside your loop

0

Author Comment

ID: 24418070
import java.io.*;
import java.util.*;

public class myArray
{
static Scanner console = new Scanner(System.in);

public static void main(String[] args)
{

int[] item = new int[26];

int range1=0, range2=0, range3=0, range4=0, range5=0, range6=0, range7=0,range8=0;
int index;
System.out.println("Enter 26 numbers:");
for (index =0; index < item.length; index++)
item[index] = console.nextInt();

if (item[index] <=24)
range1++;
else if (item[index] >= 25  && item[index] <=49)
{
range2++;
}
else if (item[index] >= 50 && item[index] <=74)
{
range3++;
}
else if(item[index] >= 75 && item[index] <=99)
{
range4++;
}
else if(item[index] >= 100 && item[index] <=124)
{
range5++;
}
else if(item[index] >= 125 && item[index] <=149)
{
range6++;
}
else if(item[index] >= 150 && item[index] <=174)
{
range7++;
}
else if(item[index] >= 175 && item[index] <=200)
{
range8++;
}

System.out.println( range1 + "Students have scores that range in the  24 and below category");
System.out.println( range2 + "Students have scores that range between 25 and 49");
System.out.println( range3 + "Students have scores that range between 50 and 74");
System.out.println( range4 + "Students have scores that range between 75 and 99");
System.out.println( range5 + "Students have scores that range between 100 and 124");
System.out.println( range6 + "Students have scores that range between 125 and 149");
System.out.println( range7 + "Students have scores that range between 150 and 174");
System.out.println( range8 + "Students have scores that range between 175 and 200");
}
}
0

LVL 92

Expert Comment

ID: 24418075

for (index =0; index < item.length; index++)
{
item[index] = console.nextInt();

if (item[index] <=24)
range1++;
else if (item[index] >= 25  && item[index] <=49)
{
range2++;
}
else if (item[index] >= 50 && item[index] <=74)
{
range3++;
}
else if(item[index] >= 75 && item[index] <=99)
{
range4++;
}
else if(item[index] >= 100 && item[index] <=124)
{
range5++;
}
else if(item[index] >= 125 && item[index] <=149)
{
range6++;
}
else if(item[index] >= 150 && item[index] <=174)
{
range7++;
}
else if(item[index] >= 175 && item[index] <=200)
{
range8++;
}
}
0

Author Comment

ID: 24418126
The program is only accepting 1 number then the system.out.println executes instead of 26  numbers. How do I create a loop that goes through until all numbers are entered  instead of just one number.
0

LVL 16

Expert Comment

ID: 24418134
Actually, I don't see why a Java array is needed in this case. You can process each score right away when the user inputs, like this:

int N = 26;
int item = 0;

for (int i=0; i<N; i++) {
item = console.nextInt();

if (item <= 24)
range1++;
// etc...
}
0

LVL 20

Expert Comment

ID: 24418457
You need to change the item.length within the for loop to item[index]. The item.length will alway return 26 which is what you r result is in the current code.
0

LVL 92

Expert Comment

ID: 24418700
> The program is only accepting 1 number then the system.out.println executes instead of 26  numbers. How do I create a loop that goes through until all numbers are entered  instead of just one number.

by making the change i posted above

0

LVL 92

Expert Comment

ID: 24418722
import java.io.*;
import java.util.*;

public class myArray {
static Scanner console = new Scanner(System.in);

public static void main(String[] args) {

int[] item = new int[26];

int range1 = 0, range2 = 0, range3 = 0, range4 = 0, range5 = 0, range6 = 0, range7 = 0, range8 = 0;
int index;
System.out.println("Enter 26 numbers");
for (index = 0; index < item.length; index++) {
item[index] = console.nextInt();

if (item[index] <= 24)
range1++;
else if (item[index] >= 25 && item[index] <= 49) {
range2++;
} else if (item[index] >= 50 && item[index] <= 74) {
range3++;
} else if (item[index] >= 75 && item[index] <= 99) {
range4++;
} else if (item[index] >= 100 && item[index] <= 124) {
range5++;
} else if (item[index] >= 125 && item[index] <= 149) {
range6++;
} else if (item[index] >= 150 && item[index] <= 174) {
range7++;
} else if (item[index] >= 175 && item[index] <= 200) {
range8++;
}
}

System.out
.println(range1
+ "Students have scores that range in the  24 and below category");
System.out.println(range2
+ "Students have scores that range between 25 and 49");
System.out.println(range3
+ "Students have scores that range between 50 and 74");
System.out.println(range4
+ "Students have scores that range between 75 and 99");
System.out.println(range5
+ "Students have scores that range between 100 and 124");
System.out.println(range6
+ "Students have scores that range between 125 and 149");
System.out.println(range7
+ "Students have scores that range between 150 and 174");
System.out.println(range8
+ "Students have scores that range between 175 and 200");
}
}
0

LVL 86

Accepted Solution

CEHJ earned 500 total points
ID: 24419185
You don't need all those if statements:
``````import java.io.*;

import java.util.*;

public class myArray {

static Scanner console = new Scanner(System.in);

public static void main(String[] args) {

int[] item = new int[8];

int range1 = 0, range2 = 0, range3 = 0, range4 = 0, range5 = 0, range6 = 0, range7 = 0, range8 = 0;

int index;

System.out.println("Enter 26 numbers");

for (index = 0; index < 26; index++) { // Don't actually use this magic number 26

int range = console.nextInt() / 25;

if (range < item.length) { // (discard out-of-bounds)

item[range]++;

}

}

// Display however you see fit

System.out.println(java.util.Arrays.toString(item));

}

}
``````
0

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