Sorting values in an array in C

Question

I am very new to programming. For an assignment I have to make a function that can sort the array in ascending order. I have written a function, however it does not work entirely. I have read a lot of questions about cases like this on this forum already (searched for bubble sort for example), however I still can't work out my problem.

my code:

void sortOnValue(float *values, int size) 
{
int i, d;
float swap;

    for (i = 0; i < (size - 1); i++)
    {
        for (d = 0; d < (size - 1 - i); d++);
        {
            if (values[d] > values[d+1])
            {
                swap = values[d];
                values[d] = values[d+1];
                values[d+1] = swap;
            }
        }
    }
}

void main()
{
int i;
float x, y;
float val[10]; //1.5, 2.2, 7.3, 9.2, 7.4, 7.5, -8.0, 1.5, 12
val[0] = 1.5;
val[1] = 2.2;
val[2] = 7.3;
val[3] = 9.2;
val[4] = 7.4;
val[5] = 7.5;
val[6] = -8.0;
val[7] = 1.5;
val[8] = 12;

printValues(val, 10);
sortOnValue(val, 10);
printValues(val, 10);
}

my output:

Values:  1.500 -8.000 2.200 7.300 9.200 7.400 7.500 0.000 1.500 12.000

Any idea why it is not working? I think it might be because the loop ends before it should, however I am not sure. Also, is there a more efficient way of assigning values to an array than what I did?

Thanks in advance for any help!

For one thing you don't initialize all elements in the array. — Some programmer dude
– Some programmer dude, Commented Sep 24, 2016 at 11:40
float val[10] = {1.5, 2.2, 7.3, 9.2, 7.4, 7.5, -8.0, 1.5, 12} ; for assigning. This way, unspecified values will also be set to 0. — MayeulC
– MayeulC, Commented Sep 24, 2016 at 11:41
Thank you! I tried that with ; seperating the values, so thanks for that tip — DaBear
– DaBear, Commented Sep 24, 2016 at 11:43
You should also learn how to use a debugger. With a debugger you can step through the code line by line while monitoring variables and their values. Being able to use a debugger is an essential skill for all programmers, no matter if it's just for a hobby or professionally. — Some programmer dude
– Some programmer dude, Commented Sep 24, 2016 at 11:45
for (d = 0; d < (size - 1 - i); d++); remove last ;. and printValues(val, 10); --> printValues(val, 9); , Pass as the size 9 instead of 10. — BLUEPIXY
– BLUEPIXY, Commented Sep 24, 2016 at 11:46

dbush · Accepted Answer · 2016-09-24 11:50:33Z

1

Look closely at this line:

   //              what's this? -------v
   for (d = 0; d < (size - 1 - i); d++);
   {

You have a stray semicolon at the end of this for. As a result, what you have here is an empty loop. Then the block below it runs every time.

Get rid of it and the program runs as expected.

As a matter of style, it's good practice to have the opening brace of a block on the same line as the statement that starts it as follows:

   for (d = 0; d < (size - 1 - i); d++) {

That helps to reduce the chances of something like this happening.

Also, if you want to initialize an array, you can do it like this:

float val[10] = { 1.5, 2.2, 7.3, 9.2, 7.4, 7.5, -8.0, 1.5, 12, 9.9 };

Note that previously you weren't initializing all 10 elements in the array. I added one more element here to fill in the whole thing.

answered Sep 24, 2016 at 11:50

dbush

233k27 gold badges261 silver badges334 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Saurav Sahu · Accepted Answer · 2016-09-24 11:50:29Z

1

Change

for (d = 0; d < (size - 1 - i); d++); and d+1

To

for ( d = i+1 ;d < size; d++) and d+i

Compare values[i] with values[d+i] and then swap accordingly.

edited Sep 24, 2016 at 11:50

answered Sep 24, 2016 at 11:43

Saurav Sahu

14.1k9 gold badges73 silver badges85 bronze badges

1 Comment

MayeulC Over a year ago

Just note that since the last value isn't initialised, removing -1 might break something in this example.

Collectives™ on Stack Overflow

Sorting values in an array in C

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related