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Cant find the mistake

The task was to write a method to return the least value of an array.
Would someone quickly look over my code?
public static int findMinimum (int [] array) {
for (int kohlrabi = 0; kohlrabi < array.length; kohlrabi++) {
for (int zwiebel= 0; zwiebel < array.length; zwiebel ++) {
if (array [zwiebel] < array [kohlrabi]) {
kohlrabi = zwiebel -1;
break;
}
int spinat = array [kohlrabi];
if (zwiebel == array.length-1) {
return spinat;
}
}
}
}
Exception in thread "main" java.lang.Error: Unresolved compilation
problem: This method must return a result of type int
at Abgabe7.ArrayExercises.findMinimum(ArrayExercises.java:38)
It's a homework for my school and I definitely understood the logic behind it but cannot find my fault.
Thanks Max

I don't think you need to have two loops. One loop would work.
Simply loop though the array keeping a variable which is the lowest you've found.

You should declare a global variable before the loop then use only one for loop in your code as follows:
int zwiebel= 0;
for (int kohlrabi = 0; kohlrabi < array.length; kohlrabi++) {
if (kohlrabi == 0){
zwiebel = array[kohlrabi];
}
if (array[kohlrabi] < zwiebel) {
zwiebel = array[kohlrabi];
}
}
The lowest value in your array is now stored in the variable zwiebel.

The real mistake is that you are not taking the possibility of an empty array into account. One thing to learn in programming is to think of all possibilities (maybe you’ve discovered that already). An array in Java (and most other languages) can have length 0, that is, have no elements in it. When array.length is 0, your outer for loop doesn’t execute, so we get down to the bottom of the method without having returned anything and without having anything to return.
Java is dumb, but nevertheless smart enough to discover this problem for you. When your method is declared to return an int, it insists that it too can see that it will return an int in all cases. In your method it cannot, which is what the following message is trying to tell you:
This method must return a result of type int
One possible fix — and I may be showing you something that you haven’t learned in school yet — is to insert the following statement in the end of your method:
throw new IllegalArgumentException("Cannot find the minimum of an empty array");
Throwing an exception is an alternative to returning a value, so this statement will make Java happy. If you actually try to find the minimum of an empty array, your program will crash and give you the message “Cannot find the minimum of an empty array”. But finding the minimum of an array that has numbers in it should work now.
That said the others are correct: Your way of finding the minimum is overly complex. I have been staring at your code and still have not understood how it works. Such code is not good. In real life you will be writing code that others will need to read and change after you, and no one can change code they don’t understand, so your code would not be useful. More important than writing code that works correctly is writing readable code.
Edit: There are variations on how to do this in a simple way. For a school exercise using a for loop I would write:
public static int findMinimum (int [] array) {
if (array.length == 0) {
return 42; // or whichever value is desired in this case
}
int niedrichsteSoWeit = array[0];
for (int index = 1; index < array.length; index++) {
if (array[index] < niedrichsteSoWeit) {
niedrichsteSoWeit = array[index];
}
}
return niedrichsteSoWeit;
}
For production code I probably would not write a method but use the built-in functionality, for example:
IntStream.of(myIntArray)
.min()
.ifPresentOrElse(min -> {
// do something with min
}, () -> {
// do whatever you want to do when the array is empty
});
Don’t worry if you don’t understand a bit of this snippet. It’s mostly for more experienced programmers who might happen to read this answer.

Count elements of a list using While loop in java

I am passing some parameters in the URL and then I add them in a list. My list has a limit of 5 elements. So if someone adds 6th element in the URL the list would simply ignore it. So I am trying to use a counter but the logic is not working as desired. I am using While loop to achieve this. So if list size is smaller than 5 set the agencyCds otherwise just return the list.
private List<IUiIntegrationDto> generateViewIntegrationReportData(ESignatureIntegrationConfig eSignConfig) throws Exception {
int counter = 1;
if(eSignConfig.getAdditionalAgencyCds() != null ) {
List<String> combinedAgencyCds = new ArrayList<String>();
for(String agencyCd : eSignConfig.getAgencyCd()) {
combinedAgencyCds.add(agencyCd);
}
StringTokenizer token = new StringTokenizer(eSignConfig.getAdditionalAgencyCds().toString(), StringConstants.COMMA);
while(token.hasMoreTokens()) {
combinedAgencyCds.add(token.nextToken());
}
while(combinedAgencyCds.size() < 5) {
counter = counter + 1;
eSignConfig.setAgencyCd(combinedAgencyCds);
}
// eSignConfig.setAgencyCd(combinedAgencyCds);
}
List<IUiIntegrationDto> intgList = getUiIntegrationManager().retrieveUiIntegrationReportData(eSignConfig.getAgencyCd(), eSignConfig.getCreatedDays(),
eSignConfig.getLob(), eSignConfig.getTransactionStatus(), eSignConfig.getAccounts(), eSignConfig.getSortKey(), eSignConfig.getSortOrder());
return intgList;
}
I am not completely sure about this logic if it is correct or if there is nay better approach.
Thanks

Try this instead of the last while in your code:
if(combinedAgencyCds.size() <= 5) {
eSignConfig.setAgencyCd(combinedAgencyCds);
} else {
eSignConfig.setAgencyCd(combinedAgencyCds.subList(0, 5));
}
The full combined list will then be used if it is less than 5 in size. Otherwise, only the first 5 elements are used.
Edit: Or even better:
eSignConfig.setAgencyCd(combinedAgencyCds.subList(0, Math.min(5, combinedAgencyCds.size())));

Ok so let's break down what your code is currently doing.
int counter = 1;
while(combinedAgencyCds.size() < 5) {
counter = counter + 1;
eSignConfig.setAgencyCd(combinedAgencyCds);
}
This snippet of code has a couple things wrong best I can tell. First, this loop has the possibility of running forever or not at all. Because combinedAgencyCds is never being manipulated, the size won't ever change and the logic being checked in the while loop never does anything. Second, there's a more efficient loop for doing this, assuming you don't need the counter variable outside of its usage in the while loop and that is using for loops.
Example syntax is as follows:
for (int i = 0; i < combinedAgencyCds.size(); i++) {
if (i < 5) {
// Do your logic here.
}
else {
break; // Or handle extra values however you want.
}
}
Notice there is no need for the explicit declaration for a counter variable as "i" counts for you.
Now in your actual logic in the loop, I'm not sure what the setAgencyCd method does, but if it simply sets a list variable in the eSignConfig like it appears to, repeating it over and over isn't going to do anything. From what I can see in your code, you are setting a variable with the same value 5 times. If you need any more explanation just let me know and I will be happy to revise the answer.

Java, repeat If statement if the condition was false

Simplified, I basically have an if statement like this:
if(A[random]==1)
A[random]=0;
else
continue;
Now I know the 'continue' is for loop statements and this won't work, but I wanted something after the else that if indeed the else(basicaly the condition was false) was activated it repeated the first if(A[random]==1) statement.

You can use a while statement instead:
while (A[random] != 1) {
A[random] = 0;
// generate a new random...
}

You can try below recursion code and see if this resolve's your query
public class Test {
public void continueIf(){
if(A[random]==1)
A[random]=0;
else {
continueIf();
}
}
public static void main(String[] args) {
new Test().continueIf();
}
}
Please note if, if condition is not satisfy then it will lead to stackoverflowerror. That too it depends on the size of JVM memory. check this link for more details on stackoverflow error.

The if/Else statement won't work by itself with looping through an array. I suggest sticking it in either a For loop or a While loop. The loop will search the array and the if/else statement will check the index for the condition provided. I would also get rid of else too. You don't really need that part just the if.
A for loop in the most basic example would look something like this:
for(var i = 0; i < SIZE; i++)
{
if (A[i] == 1)
A[i] = 0;
}
SIZE would be the size of your array

random = ...; // get first random number
while (A[random] != 1) {
random = ...; // get new random number
}
A[random] = 0; // now is 1, switch it to 0

This should work.The other answers have described while and recursion so i am
also adding a do while loop.
do{
//generate the random number
}while(A[random]!=1)//The loop iterates till the condition A[random]!=1 is satisfied
A[random]==0;//changing the bit to 0
Please note that if there is no bit =1 in the array then this solution will fail because you are generating indexes randomly.
So if the array has no element =1 then it keeps on checking the indexes repeatedly and generates infinite loop.
Hope it helps.happy coding!!

In an array with null spaces, how can consolidate all of the non null values together?

Hey so I have this homework assignment and I'm having issues with one of the methods. I would like hints and not actual answers/code.
So I have a class called HorseBarn that messes with an array of horses(horse being the type). My problem is I'm having troubles with the consolidate method.
What the array would look like before consolidate:
a,b,c,d are horses
|a|null|b|null|c|d|
What the array would look like after consolidate:
|a|b|c|d|null|null|
So my logic would be to make a nested for loop. The first loop would search for a null value, once the first loop finds the null value, the second loop would look for a horse and then swap with it. Then the second loop would end and go back to the first loop. So here is what I have right now and it doesn't work(it just terminates). Is my logic wrong or is it my syntax that's causing the problems?
public void consolidate()
{
int j = 0;
for(int i = 0; i < spaces.length;i++)
{
if( spaces[i] == null)
{
for(j = i; j < spaces.length && spaces[j] == null; j++)
{
}
spaces[i] = spaces[j];
spaces[j] = null;
}
}

Well for starters, this should give an index out of bounds exception if the last non-null is found and there still are elements remaining:
ex: horses = | a | null | null | null |
for i = 1, since horses[1] -> horses[3] are empty, j first gets set to 1 then ends with j = 4 (because of the termination condition j < horses.length())
You would then try to swap horses[1] with horses[4], which throws the array index out of bounds

In the inner for loop, just find the position of next non null value and break it there.
Then swap it with your null.
A better time efficient code.

iterator for loops with break

let say my code look like below
for(..)
for(..)
for(..){
break; //this will break out from the most inner loop OR all 3 iterated loops?
}

Your example will break out of the innermost loop only. However, using a labeled break statement, you can do this:
outer:
for(..)
for(..)
for(..){
break outer; //this will break out from all three loops
}

This will only break out from the inner loop. You can also define a scope to break out from. More from the language specs:
A break statement with no label
attempts to transfer control to the
innermost enclosing switch, while, do,
or for statement of the immediately
enclosing method or initializer block;
this statement, which is called the
break target, then immediately
completes normally.

Yes, without labels it will break only the most inner loop.
Instead of using labels you can put your loops in a seperated function and return from the function.
class Loop {
public void loopForXx() {
untilXx();
}
private void untilXx() {
for()
for()
for()
if(xx)
return;
}
}

From the most inner loop :)
int i,j,k;
for(i = 0; i < 2; i++)
for(j = 0; j < 2; j++)
for(k = 0; k < 2; k++)
{
printf("%d %d %d\n", i, j, k);
break;
}
Will produce :
0 0 0
0 1 0
1 0 0
1 1 0

You should take a look here: http://java.sun.com/docs/books/tutorial/java/nutsandbolts/branch.html

as often mentioned i don't like to break with a label eather. so while in a for loop most of the time i'm adding a boolean varible to simple exit the loop.. (only if i want to break it of cause;))
boolean exit = false;
for (int i = 0; i < 10 && !exit; i++) {
for (int j = 0; j < 10 && !exit; j++) {
exit = true;
}
}
this is in my opinion more elegant than a break..

Many people here don't like labels and breaking. This technique can be compared to using a 'goto' statement, a flow control statement which allows jumping out of a block of code in a non-standard way, obliviating use of pre- and post conditions. Edsger Dijkstra published a famous article in Communications of the ACM, march 1968, 'Goto statement considered harmful' (it's a short read).
Using the same reasoning presented in the article, returning from inside an iteration as suggested by TimW is also bad practice. If one is strict, to create readable code, with predictable entry- and exit points, one should initialize the variable which will hold the return value (if any) at the beginning of the method and return only at the end of a mehod.
This poses a challenge when using an iteration to perform a lookup. To avoid using break or return one inevitably ends up with a while-loop with a regular stop condition and some boolean variable to indicate that the lookup has succeeded:
boolean targetFound = false;
int i = 0;
while (i < values.size() && ! targetFound ) {
if (values.get(i).equals(targetValue)) {
targetFound = true;
}
}
if (!targetFound) {
// handle lookup failure
}
Ok, this works, but it seems a bit clunky to me. First of all I have to introduce a boolean to detect lookup success. Secondly I have to explicitly check targetFound after the loop to handle lookup failure.
I sometimes use this solution, which I think is more concise and readable:
lookup: {
for(Value value : values) {
if (value.equals(targetValue)) {
break lookup;
}
}
// handle lookup failure here
}
I think breaking (no pun intended) the rule here results in better code.

it will breake from most inner loop,
if you want to break from all, you can hold a variable and change its value when you want to break, then control it at the beginning of each for loop