how can i get rid of: warning: value computed is not used [-Wunused-value]

Question

I'm a beginner in programming so I would like a simple answer :)

I have a for loop with multiple conditions, which prints out two arrays. It works, but i get a warning and a red line under for(). Why is it so and how can I avoid it? I'm writing it in C and I use a Geany compiler in Ubuntu. :)

for((i=LEN-1) && (j=1); (i>=LEN-3) && (j<=PODIUM); i-- && j++)  
{       
  printf("%d. koht: %s tulemusega %f\n", j, voist[i], tul[i]);      
}

you need to change `(i=LEN-1) && (j=1)` to `i=LEN-1,j=1` and `i-- && j++` to `i--,j++` — SHR, Nov 28 '13 at 14:05

haccks · Answer 1 · 2013-11-28T14:15:09.773

0

This warning is because of the return value of (i=LEN-1) && (j=1) which is bot used further.To avoid the warning, try this

int temp;
... 

temp = (i=LEN-1) && (j=1);

for(; (i>=LEN-3) && (j<=PODIUM); i-- && j++)  
{  

     ....

     temp = (i=LEN-1) && (j=1);
}

edited Nov 28 '13 at 14:15

answered Nov 28 '13 at 14:03

haccks

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Unfortunately that just adds another warning :) variable temp set but not used. – Jaan Nov 28 '13 at 14:07

SHR · Accepted Answer · 2013-11-28T14:18:50.090

0

for(i=LEN-1,j=1 ; (i>=LEN-3) && (j<=PODIUM); i--, j++)

EDIT: It works because this is the correct syntax. you don't need to use and operator to combine two initializations or two increments. you can just use the ,

edited Nov 28 '13 at 14:18

answered Nov 28 '13 at 14:11

SHR

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this solution worked. but why does it work? can you explain? :) – Jaan Nov 28 '13 at 14:14
The compiler was storing the boolean result in some temp variable internally , which was never used . When we remove the boolean conditions for first , last arguments of for it solves the purpose ! – Srikanth Nov 28 '13 at 14:18

how can i get rid of: warning: value computed is not used [-Wunused-value]

2 Answers2