How do I match 2 files to print data.

I am having problems getting two file to match once they have been sorted. The 2 files have one record in common and that is an Id number(CustomerId and orderId).
CustomerId File contains:

CustomerId
CustomerFirstName
CustomerMiddleName
CustomerLastName
CustomerAddress
CityStateZip
CustomerPhoneNo
CustomerEmailAddress

order file contains:

orderId
length
width
carpetCharge
discount

The 2 Id numbers match but the wrong information is being printed from the CustomerId file.

Any ideas?

The following is what I have:

Code:

---

if(CustomerId = orderId)
{
fprintf(processFilePtr, "%c", 179);
        fprintf(processFilePtr, "Customer Id:  %9s %53s %c\n", CustomerId, "", 179);
        fprintf(processFilePtr, "%c", 179);
        fprintf(processFilePtr, "Order Id:  %9s %56s %c\n", orderId, "", 179);
        fprintf(processFilePtr, "%c %76s %c\n", 179, "", 179);
        fprintf(processFilePtr, "%cFirst Name:  %10s %53s%c\n", 179, CustomerFirstName, "", 179);
        fprintf(processFilePtr, "%cMiddle Name:  %10s %53s%c\n", 179, CustomerMiddleName, "", 179);
        fprintf(processFilePtr, "%cLast Name:    %10s %52s %c\n", 179, CustomerLastName, "", 179);
        fprintf(processFilePtr, "%c %76s %c\n", 179, "", 179);
        fprintf(processFilePtr, "%cAddress:      %25s %37s %c\n", 179, CustomerAddress,
                "", 179);
        fprintf(processFilePtr, "%c              %25s %37s %c\n", 179, CityStateZip,
                "", 179);
        fprintf(processFilePtr, "%c %76s %c\n", 179, "", 179);
        fprintf(processFilePtr, "%cPhone No:      %15s %45s %c\n", 179, CustomerPhoneNo,
                "", 179);
        fprintf(processFilePtr, "%cEmail Address: %25s %35s %c\n", 179, CustomerEmailAddress,
                "", 179);
        fprintf(processFilePtr, "%c", 195);
        HorizontalLine(processFilePtr);
        fprintf(processFilePtr, "%c\n", 180);
        fprintf(processFilePtr, "%c", 179);
        fprintf(processFilePtr, "%37s MEASUREMENT %28s", "", "");
        fprintf(processFilePtr, "%c\n", 179);
        if(CustomerId = orderId)
        {
        fprintf(processFilePtr, "%c %76s %c\n", 179, "", 179);
        fprintf(processFilePtr, "%c %25s Length %20s %d ft %16s %c\n",
                179, "",  "", length, "", 179);
        fprintf(processFilePtr, "%c %25s Width %21s %d ft %16s %c\n",
                179, "",  "", width, "", 179);
        fprintf(processFilePtr, "%c %25s Area %21s %d ft %16s %c\n",
                179, "",  "", area, "", 179);
}//end if

---