cat program in c

cat.c

#include <stdio.h>

int main(int argc, char *argv[]) {
    FILE *fp;
    
    void filecopy(FILE *, FILE *);
    
    char *prog = argv[0];
    
    if (argc == 1)
        filecopy(stdin, stdout);
    else
        while(--argc > 0)
            if ((fp = fopen(*++argv, "r")) == NULL) {
                fprintf(stderr, "%s: can't open %s\n", prog, *argv);
                return 1;
            } else {
                filecopy(fp, stdout);
                fclose(fp);
            }
    if (ferror(stdout)) {
        fprintf(stderr, "%s: error writing stdout\n", prog);
        return 2;
    }
    return 0;
}

void filecopy(FILE *ifp, FILE *ofp) {
    int c;
    
    while ((c = getc(ifp)) != EOF)
        putc(c, ofp);
}