如何在C中读取和比较字符255

Question

I need to write a code that searches all the aparition of a string in a file. Recently, my teacher told me to search string (char)255(char)255 in a file with the same string. The problem is that I can not read those characters and badly, I cannot distinguish or compare those caracter to EOF; My code for searching the given string in a file is :

//problema 14

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[]) {

    char b;
    int k=0;
    if(argc!=3) {
        fprintf(stderr,"Utilizare: %s fisier sir\n",argv[0]);
        return 1;
        }  
    if(argv[2][0]=='\0'){
        fprintf(stderr, "String vid\n");
        return 1;
    }

    FILE *f;
    f=fopen(argv[1],"r");
    if (!f)
    {
        perror(argv[1]);
        return 1;
    }


    int i=0;

    while((b = fgetc(f))!=EOF)
    {

        if(b==argv[2][i]) i++;
        else {
            fseek(f,-i, SEEK_CUR);
            i=0;
        }

        if(argv[2][i]=='\0'){
            k++;
            fseek(f,-i+1, SEEK_CUR);
            i=0;
        }



    }
    printf("\nSULFUS %d APPEARANCES\n",k);
    return EXIT_SUCCESS;
}

what can I do with this code to work on comparint string of (char)255 characters?

Answer 1

The trick is to realize that fgetc returns an int .

So, change the data type of b to int !

Answer 2

But then, "while" does nothing, because it seems that 255 is also recognized as EOF or it goes infinite. I tried also with int but I couldn't figure out much...This teacher is like a compilator, he likes to put you in trouble.