extra symbol [bug]

#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <stdlib.h>

void printfile(char *file);

int main(int argc, char *argv[])
{
    if (argc==1)
    {
        fprintf(stderr, "usage: printfiles file1 [file2 ...]\n    file1, file2, etc.: files to print\n");
        exit(EINVAL);
    }
    int i;
    for (int i = 1; i < argc; ++i)
    {
        printfile(argv[i]);
    }
    exit(0);
    return 0;
}

void printfile(char *file){
    assert(file!=NULL);
    FILE *fp = fopen(file, "rb");
    if (!fp)
    {
        fprintf(stderr, "Can't open input file %s!\n", file);
        exit(ENOENT);
    }
    char buff;
    while (!feof(fp)){
        buff = fgetc(fp);
        printf("%c", buff);
    }
    printf("\n");
    fclose(fp);
}