CODEWITHSUNDEEP
javatemporary-objects
user2420262
user2420262

Reputation: 11

How to swap more than two variables using temporary variables

I'm trying to figure out how to swap more than two variables around using a temp variable. There are 4 variables to be swapped, 1,2,3 and 4. Variable one is to swap with 2, 2 with 3, 3 with 4 and 4 with 1. It seems simple enough but I've only learnt how to swap two variables so and am struggling with the larger scale. I've tried 

temp = 1
1 = 2
temp = 2 
2 = 3 
temp = 3
3 = 4
temp = 4
4 = 1

Do i need more than one temp variable? Still only a beginner any help would be appreciated!

Edit: Sorry, forgot to add I'm coding for java.

Upvotes: 1

Views: 4590

Answers (3)

AllTooSir
AllTooSir

Reputation: 49372

An array is a better approach for your requirement . In your present pseudo code , you can do something like this :

temp = 1
1 = 2
2 = 3 
3 = 4
4 = temp

In java , you can do something like below using array :

int[] x = {5,15,25,35};
int temporary = x[0];
for(int j=0;j<x.length-1;j++){
    x[j]=x[j+1];
}
x[x.length-1]=temporary;

Upvotes: 1

tom
tom

Reputation: 22949

Consider what happens in the third step. The original value of 1 (which was saved to temp in the first line) is lost, because you overwrite temp with the value of 2.

As it turns out, there is no need to save a copy of the original value of 2 because there is already a copy in 1. The same applies to all the other variables (except 1).

So the only time you need to use temp is at the very start to save the value of 1 (like you are currently doing), and also at the very end when you assign the original value of 1 to 4. You can't use 1 because it was overwritten, but a copy was saved in temp just for this purpose.

So the final code looks like this:

temp = 1
1 = 2
2 = 3 
3 = 4
4 = temp

Upvotes: 1

user529758
user529758

Reputation:

Just use an array along with a loop and one temporary variable will be enough. P-code since you didn't mention the language:

array = { 1, 2, 3, 4 }
tmp = array[0]
for i in [0, array.count - 1)
    array[i] = array[i + 1]
array[array.count - 1] = tmp

Upvotes: 1

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