I am by rights a VB programmer, and am trying to write a c++ routine to sort some data. I need help with trying to figure out:
1) how to use VectorFromBstr, I added the oleauto.h file, but I still get undeclared identifier..
2) how to write my custom compare function for qsort, listed far below, to compare each field of the type Patient..
Before that, a little background:
I have a file of patient data, written by the following VB type:
My VB program does not sort the records in the file, but instead loads the file contents into memory, and sort them, in memory. I then run through the sorted array of patient records, writing the UPI's to an index file.Code:Type P1 LName As String * 16 'last name FName As String * 12 'first name MName As String * 1 'middle initial BDate As String * 10 'birthdate NDate As String * 10 'next office visit Upi As Integer 'unique patient identifier End Type
(bare with me here)
As an example if I have three patients, John with UPI of 5343 , Brad with UPI of 9232, Tim with UPI of 2322, the array would be sorted, and index file would contain:
9232
5343
2322
OK, now, what I did above, I want to accomplish in C++, which is basically: open the patient file, read in the file, qsort the patients, and write the sorted UPI's(which are just integers) to file.
So this is what I have so far:
As you can see, I am using qsort... which I was advised to use to sort these. So here's my compare function:Code:typedef struct patient { BSTR Lname; BSTR Fname; char Mname; BSTR Bdate; BSTR Ndate; int Upc; }p; int cmp(const void*,const void *); int main(){ struct patient *first,*a,*b; FILE *in,*out; int nelem; struct stat statbuf; struct stat *s; s=&statbuf; in = fopen("patient.dat","rb"); stat("patient.dat",s); first = (p*) malloc( s->st_size ); fread(first,s->st_size,1,in); nelem = (int)(s->st_size / (long)sizeof(p) ); qsort(first,nelem,sizeof(p),cmp ); //need to modify code below to run through //struct array and write out only the UPI's of the //sorted array. out=fopen("patient_sorted.dat","wb"); fwrite(first,sizeof(p),nelem,out); fclose(in); fclose(out); free(first); return 0; }
I need to compare the last names, if they are equal:
compare the first names, if they are equal:
compare middle initals, if equal:
compare birthdates, if equal:
compare UPI's (which are never equal),
If any of the above are not equal, it returns a value to qsort.
Custom compare function I wrote for qsort
Code:int cmp(const void *a, const void *b){ //custom compare routine int j; char tmp[40],tmp1[40]; char *working,*working1; struct patient *s; struct patient *t; zout(tmp); zout(tmp1); s = (struct patient*)a; //the below code converts bstr into a vector passing it //to safearray working? But then how do I strcomp then? HRESULT i = VectorFromBSTR(s->Lname,working); //below code does the same as above code for 2nd patient t=(struct patient*)b; i = VectorFromBSTR(s->Lname,working1); j =strcmp( ? ); //compare last names if j < 0 || j > 0 'if last names are not equal return j; if j == 0 { //compare first names //need code here to set tmp,tmp1 to fnames j=strcomp(tmp,tmp1) if j < 0 || j > 0 'if first names are not equal return j; if j == 0 { //compare middle initials //need code here to set tmp,tmp1 to middleinitial j=strcomp(tmp,tmp1) if j < 0 || j > 0 'if middle init's are not equal return j; if j == 0 { //compare birthdates **the dates are stored as strings remember //ie. 11/20/2000 or 02/31/1995 //need code here to set tmp,tmp1 to bdates j=strcomp(tmp,tmp1) if j < 0 || j > 0 'if birthdates's are not equal return j; if j == 0 { //compare UPI (unique patient identifier, which is an integer) //no two UPI's are the same, so one will //always be greater or lesser than another return j; }//end UPI comparison }//end birthdate comparison } // end middle initial comparison }//end firstname comparison } //end lastname compare }//end custom compare function
