C warning with char array: "warning: array subscript has type 'char'"

Question

I am confused as to why this error occurs. My code execute fine and the results is exactly what I want but on compiling my c file with the command: "gcc -std=c99 -Wall -o assignment2 assignment2.c"

Here is the code:

Here is the output error:

I would just use this but i'm sure it might have some reasons why an error shows and also because my assignment marker probably want accept it if there is this warning on compilation.

Why is i a char?

Iharob Al Asimi
– Iharob Al Asimi

2017-03-16 02:10:28 +00:00
Commented Mar 16, 2017 at 2:10 — Iharob Al Asimi
– Iharob Al Asimi, Commented Mar 16, 2017 at 2:10

David Ranieri · Accepted Answer · 2017-03-16 02:15:12Z

5

If you are using i for a counter, use int instead of char

int i = 0;

this will fix the problem.

But also, c should be an int, because fgetc() can return EOF which is an int, and in general the return type of fgetc() is int, thus you should use int for c too.

Your code should be then

char word[500];
int i = 0;
int c;

while (((c = fgetc(fp)) != EOF) && (c != '\n')) {
    word[i++] = (char) c;
}
word[i] = '\0';

edited Mar 16, 2017 at 2:15

David Ranieri

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answered Mar 16, 2017 at 2:10

Iharob Al Asimi

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3 Comments

Iharob Al Asimi Over a year ago

@KeineLust, the code had Undefined Behavior, thanks for the edit.

jjyj Over a year ago

Oh man, I was trying this and that from other answers online and ended up missing this little mistake. Thanks a lot for pointing that out for me.

Iharob Al Asimi Over a year ago

@jjyj That's what Stack Overflow is for, and it's fun to help. But keep in mind, that you should post actual code instead of images next time.

Johanneke · Accepted Answer · 2017-06-07 17:29:45Z

-2

i should be evaluated so that i < 500 is fullfilled

edited Jun 7, 2017 at 17:29

Johanneke

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answered Jun 7, 2017 at 12:15

jinlong

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