Unknown Error(c-lang), while reading a character from file

I wrote a code in C to read a character from external .txt file. The codes are given below.

#include<stdio.h>

void main()
{
FILE *in;
unsigned char ch;
in=fopen("file.txt","r");
while((ch=fgetc(in))!=EOF)
{
printf("%c",ch);
}
}

after campile it gave the warning :
(ch=fgetc(in))!=EOF) is always true and would be in infinite loop.

But when I removed the unsigned declaration of ch it works fine.

Please, tell me , Why did it give me Warning like that ?

EOF typically is the integer value -1.

Since you defined unsigned char ch; the variable ch is an unsigned value, which will never be able to be -1.

Also...try remember to post your code inside of [code] tags. And also try to keep questions pertaining to C in the C forums (this is the C++ forum).

Also remember to use int main() instead of void main().