Thread: returning file pointer

Code:

FILE* open(const char filename[]) {
      FILE* fp;
      char c[10];
      printf(filename);
      fp = fopen(filename, "r");
      if (fp == NULL) {
         cout << " cannot open ";
      }
      else {
         cout << " opened\n";
      } 
      return fp; 
}

i need to make it like if i doesnt equal NULL it returns the pointer but if i does equal NULL i need to return false

also i can only use one exit (one return)

Since you're using cout, this isn't C code, so it should be in the C++ forum.

If you want to return false, you need to return a bool instead of a FILE*, but what's wrong with just returning NULL?

BTW, since this is C++ code, using an fstream instead of fopen() would be more object oriented...

ya thats true, i think i just made it seem hard but can someone check out this function and tell me if there is anything wrong because i get a "Segmentation fault":

Code:

int valid(const char* str){
    //char f[12];
    int k[10], d[10], sum=0, ret=0, lenght = strlen(str);
    if (strcmp(str, "0") == 0) {
                ret = 0;
            }
    if (strcmp(str, "") == 0) {
                ret = 0;
            }
    if (str == NULL) {
                ret = 0;
            }
    if (lenght != 10) {
                ret = 0;
            }
    //strcpy(f, str);
    for(int e=0;e<10;e++){
            k[e] = str[e];
            k[e] = k[e] - 48;
    }
    d[0] = k[0] * 10;
    d[1] = k[1] * 9;
    d[2] = k[2] * 8;
    d[3] = k[3] * 7;
    d[4] = k[4] * 6;
    d[5] = k[5] * 5;
    d[6] = k[6] * 4;
    d[7] = k[7] * 3;
    d[8] = k[8] * 2;
    d[9] = k[9] * 1;
    sum = (d[0] + d[1] + d[2] + d[3] + d[4] + d[5] + d[6] + d[7] + d[8] + d[9]) &#37; 11;
    if(sum==0){
               ret = 1;
               }
    else{
               ret = 0;
               }
    
    return ret;
}

i made the changes

Code:

int valid(const char* str){
    int k[10], d[10], sum=0, ret=0, lenght = strlen(str);
    if (str == NULL) {
                ret = 0;
    }
    else if (strcmp(str, "") == 0) {
                ret = 0;
    }
    else if (lenght != 10) {
                ret = 0;
    }
    else {
         for(int e=0;e<10;e++){
            k[e] = str[e];
            k[e] = k[e] - '0';
         }
         d[0] = k[0] * 10;
         d[1] = k[1] * 9;
         d[2] = k[2] * 8;
         d[3] = k[3] * 7;
         d[4] = k[4] * 6;
         d[5] = k[5] * 5;
         d[6] = k[6] * 4;
         d[7] = k[7] * 3;
         d[8] = k[8] * 2;
         d[9] = k[9] * 1;
         sum = (d[0] + d[1] + d[2] + d[3] + d[4] + d[5] + d[6] + d[7] + d[8] + d[9]) % 11;
         if(sum==0){
               ret = 1;
         }
         else{
               ret = 0;
         }
    }
    return ret;
}

but i get the same segmentation fault

ya its working now, i used the last method works perfect now man thanks