Error passing and getting Array values in Java
How I pass an array to another array?
I need to pass an array of double values but I don't know why it doesn't work.
This is my code:
private double Total_cost()
double cost=new double[2];
.
.
.
cost[0]=tot_cost;
cost[1]=tot_cost2;
return cost;
Calling the method:
public void estr_grdcmpabs()
//
double cost_grd=new double[2];
.
.
.
cost_grd= Total_cost();
cst = String.valueOf(cost_grd[0]);
I get the error:
Exception in thread "main" java.lang.NullPointerException
How I convert the array value to a string to show in jframe?
Thanks.
java arrays methods
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
add a comment |
How I pass an array to another array?
I need to pass an array of double values but I don't know why it doesn't work.
This is my code:
private double Total_cost()
double cost=new double[2];
.
.
.
cost[0]=tot_cost;
cost[1]=tot_cost2;
return cost;
Calling the method:
public void estr_grdcmpabs()
//
double cost_grd=new double[2];
.
.
.
cost_grd= Total_cost();
cst = String.valueOf(cost_grd[0]);
I get the error:
Exception in thread "main" java.lang.NullPointerException
How I convert the array value to a string to show in jframe?
Thanks.
java arrays methods
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
cost_grd[i]is adoublebutTotal_cost()returns adouble(i.e. an array), so the assignment doesn't work. What are you actually trying to do?
– arshajii
Nov 15 '18 at 20:58
I need to pass an array to an array.
– reymagnus
Nov 15 '18 at 21:01
A variable declared asnew double[1]has only one element, and its index is 0. Indexing it at 1 will throw an exception.
– Klitos Kyriacou
Nov 15 '18 at 21:03
Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 21:11
add a comment |
How I pass an array to another array?
I need to pass an array of double values but I don't know why it doesn't work.
This is my code:
private double Total_cost()
double cost=new double[2];
.
.
.
cost[0]=tot_cost;
cost[1]=tot_cost2;
return cost;
Calling the method:
public void estr_grdcmpabs()
//
double cost_grd=new double[2];
.
.
.
cost_grd= Total_cost();
cst = String.valueOf(cost_grd[0]);
I get the error:
Exception in thread "main" java.lang.NullPointerException
How I convert the array value to a string to show in jframe?
Thanks.
java arrays methods
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
How I pass an array to another array?
I need to pass an array of double values but I don't know why it doesn't work.
This is my code:
private double Total_cost()
double cost=new double[2];
.
.
.
cost[0]=tot_cost;
cost[1]=tot_cost2;
return cost;
Calling the method:
public void estr_grdcmpabs()
//
double cost_grd=new double[2];
.
.
.
cost_grd= Total_cost();
cst = String.valueOf(cost_grd[0]);
I get the error:
Exception in thread "main" java.lang.NullPointerException
How I convert the array value to a string to show in jframe?
Thanks.
java arrays methods
java arrays methods
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
edited Nov 15 '18 at 22:34
reymagnus
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
asked Nov 15 '18 at 20:55
reymagnusreymagnus
155
155
cost_grd[i]is adoublebutTotal_cost()returns adouble(i.e. an array), so the assignment doesn't work. What are you actually trying to do?
– arshajii
Nov 15 '18 at 20:58
I need to pass an array to an array.
– reymagnus
Nov 15 '18 at 21:01
A variable declared asnew double[1]has only one element, and its index is 0. Indexing it at 1 will throw an exception.
– Klitos Kyriacou
Nov 15 '18 at 21:03
Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 21:11
add a comment |
cost_grd[i]is adoublebutTotal_cost()returns adouble(i.e. an array), so the assignment doesn't work. What are you actually trying to do?
– arshajii
Nov 15 '18 at 20:58
I need to pass an array to an array.
– reymagnus
Nov 15 '18 at 21:01
A variable declared asnew double[1]has only one element, and its index is 0. Indexing it at 1 will throw an exception.
– Klitos Kyriacou
Nov 15 '18 at 21:03
Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 21:11
cost_grd[i] is a double but Total_cost() returns a double (i.e. an array), so the assignment doesn't work. What are you actually trying to do?– arshajii
Nov 15 '18 at 20:58
cost_grd[i] is a double but Total_cost() returns a double (i.e. an array), so the assignment doesn't work. What are you actually trying to do?– arshajii
Nov 15 '18 at 20:58
I need to pass an array to an array.
– reymagnus
Nov 15 '18 at 21:01
I need to pass an array to an array.
– reymagnus
Nov 15 '18 at 21:01
A variable declared as
new double[1] has only one element, and its index is 0. Indexing it at 1 will throw an exception.– Klitos Kyriacou
Nov 15 '18 at 21:03
A variable declared as
new double[1] has only one element, and its index is 0. Indexing it at 1 will throw an exception.– Klitos Kyriacou
Nov 15 '18 at 21:03
Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 21:11
Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 21:11
add a comment |
2 Answers
2
active
oldest
votes
The size of the cost array is 2 but you have declared it of size 1. This will create ArrayIndexOutOfBoundsException.
Replace the loop with this single statement so that the return type double matches
cost_grd= Total_cost();
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
add a comment |
Cost is an array of doubles, while cost_grd[i] is just a double element in the cost_grad array of doubles
To solve either change the statement to
cost_grd[i]= Total_cost()[i];
Or remove the loop and change to:
cost_grd= Total_cost();
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The size of the cost array is 2 but you have declared it of size 1. This will create ArrayIndexOutOfBoundsException.
Replace the loop with this single statement so that the return type double matches
cost_grd= Total_cost();
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
add a comment |
The size of the cost array is 2 but you have declared it of size 1. This will create ArrayIndexOutOfBoundsException.
Replace the loop with this single statement so that the return type double matches
cost_grd= Total_cost();
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
add a comment |
The size of the cost array is 2 but you have declared it of size 1. This will create ArrayIndexOutOfBoundsException.
Replace the loop with this single statement so that the return type double matches
cost_grd= Total_cost();
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
The size of the cost array is 2 but you have declared it of size 1. This will create ArrayIndexOutOfBoundsException.
Replace the loop with this single statement so that the return type double matches
cost_grd= Total_cost();
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
answered Nov 15 '18 at 21:13
AMOGH KALYANSHETTIAMOGH KALYANSHETTI
583
583
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
add a comment |
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
Ok, but now I get this error in code: Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 22:34
add a comment |
Cost is an array of doubles, while cost_grd[i] is just a double element in the cost_grad array of doubles
To solve either change the statement to
cost_grd[i]= Total_cost()[i];
Or remove the loop and change to:
cost_grd= Total_cost();
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
add a comment |
Cost is an array of doubles, while cost_grd[i] is just a double element in the cost_grad array of doubles
To solve either change the statement to
cost_grd[i]= Total_cost()[i];
Or remove the loop and change to:
cost_grd= Total_cost();
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
add a comment |
Cost is an array of doubles, while cost_grd[i] is just a double element in the cost_grad array of doubles
To solve either change the statement to
cost_grd[i]= Total_cost()[i];
Or remove the loop and change to:
cost_grd= Total_cost();
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
Cost is an array of doubles, while cost_grd[i] is just a double element in the cost_grad array of doubles
To solve either change the statement to
cost_grd[i]= Total_cost()[i];
Or remove the loop and change to:
cost_grd= Total_cost();
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
answered Nov 15 '18 at 20:59
Hossam26644Hossam26644
566
566
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
add a comment |
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
Another error, size is one while you are trying to put two elements, just change the size of cost_grd and cost to two
– Hossam26644
Nov 15 '18 at 21:13
add a comment |
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cost_grd[i]is adoublebutTotal_cost()returns adouble(i.e. an array), so the assignment doesn't work. What are you actually trying to do?– arshajii
Nov 15 '18 at 20:58
I need to pass an array to an array.
– reymagnus
Nov 15 '18 at 21:01
A variable declared as
new double[1]has only one element, and its index is 0. Indexing it at 1 will throw an exception.– Klitos Kyriacou
Nov 15 '18 at 21:03
Exception in thread "main" java.lang.NullPointerException
– reymagnus
Nov 15 '18 at 21:11