Declared Error

Im trying out using headers, and it seems that my program cant find anything in it.

Code:

---

//in filecheck.cpp
if (check("test.txt")) {
    [does this]
}

//in check.h
int check(const char *filename) {
        FILE* fp;
        if ((fp = fopen( filename, "r")) != NULL) {
                fclose(fp);
                return 1;
        }
        return 0;
}

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Every time I try to use a function in my header, my compiler just says that its undeclared and wont compile. Accually, it says nothing in my header is undeclared. Am I supposed to use something special in my file other then ' #include"check.h" ' or what?

Code:

---

//test.h
int check(const char *);
 
//in test.cpp
int check(const char * filename)
{
  ifstream fin(filename);
  if(!fin)
        cout << "unable to open file" << endl;
  else
        cout << "file open" << endl;
 
  return 0;
}

---

Thanks, that worked, but I was trying to put function in the header, and it seems I forgot the 'n' in #ifndef :rolleyes:
Now I have one more error. I tried adding a load function into the header, and now it says:

Quote:

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undefined reference to 'load(char const*)'

---

Now whats wrong?

Code:

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//in test.cpp, nothing special
load("test.txt");

//in test.h
void load(char *filename) {
    [does this]
}

---

headers in C are for prototypes (what has been explained above)
in your second example, the prototype shoule be in the header and the implementation in the cpp file (just like the first example).

Also, you are passing a const char* to a function that takes a char*.