How to get float from file using getc() in C?

I have a file with ";" as a separator, i want to get some characters and save them as float, I've come up with something like this:

int c;
char help[10];
float x;
while(getc(c)!=';'){
strcpy(help, c);
}
float = atof(help);

Correct usage of getc. It is int getc(FILE *stream). So you need to provide the stream from which it reads.

while(getc(c)!=';'){ <-- wrong
   strcpy(help, c);  <-- wrong
   ...

is wrong. The second parameter to strcpy should be a nul termnated char array.

char cs[]={c,0}
strcpy(help,cs);

or even better^{alk suggested}

{strcpy(help, (char[2]){c});}

About the input part you can do this though:

 while((c=getc(stdin))!=';'){ 
   ...

Instead of using atof it is much better to use strtof or strtod functions. They provide error checking unlike these ato* functions.