Integer division returns 0 in C

Question

An integer division caused by the elements of an array returns 0, I'm supposed to store the % in the same array....

array[6][i]=array[5][i]/total;

This stores a 0... I thought it had something to do with the array being an integer array... so I did a cast...

array[6][i]=(int)(array[5][i]/total);

Still stored 0... I read I had to convert them to floating points but the casting doesn't work... I tried this

array[6][i]=(int)((float)array[5][i]/(float)total);

the array declaration

int arreglo[7][5]={{1,194,48,206,45},{2,180,20,320,16},{3,221,90,140,20},{4,432,50,821,14},{5,820,61,946,18},{0,0,0,0,0},{0,0,0,0,0}};

and the last one will store each percentaje

Can we see two things: 1. the array declaration, and 2. maybe some of the data you've put in it? — Clinton Pierce, Nov 07 '12 at 21:39
If `total` is larger in absolute value than `array[5][i]`, the quotient _should_ be 0. — Daniel Fischer, Nov 07 '12 at 21:39
When you write "I'm supposed to store the % in the same array.", do you mean percent or remainder (modulo)? — Daniel Fischer, Nov 07 '12 at 21:41
Does this answer your question? [What is the behavior of integer division?](https://stackoverflow.com/questions/3602827/what-is-the-behavior-of-integer-division) — anthony sottile, Nov 01 '20 at 23:10

score 3 · Answer 1 · answered Nov 07 '12 at 21:42

3

If you want a percentage, then what you're looking for is something like

array[6][i] = (int) (100 * ((float)array[5][i] / (float)total));

answered Nov 07 '12 at 21:42

prprcupofcoffee

thedayofcondor · Answer 2 · 2012-11-07T23:32:41.107

2

This will always return 0.

If you are working with ints, and you divide by the total, the result will be <1 and truncated to 0 (as the result must be an integer).

You have to either use doubles (or floats) arrays, or scale the integers by a factor of eg 100 (not the total)

edited Nov 07 '12 at 23:32

answered Nov 07 '12 at 21:42

thedayofcondor

This can also return 1. Also, make sure to mention that this truncates instead of rounding. – Nov 07 '12 at 21:48
Yes, can return 1 in the limit case when the array is all empty with the exception of a single, non-zero element. – thedayofcondor Nov 07 '12 at 21:50
Also when some elements cancel each other ie {-2,7,1,1} total =7 – thedayofcondor Nov 07 '12 at 23:31

2 Answers2