我正在尝试编译我的代码并继续解决这个错误：
Error 1 error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class iOrder const &)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@ABViOrder@@@Z) referenced in function _main C:\Users\on3m1_000\documents\visual studio 2013\Projects\Assign4\Assign4\a4main.obj Assign4
我完全不确定为什么会这样。我在该错误中看到的唯一一个看起来就像在我的代码中一样远的是iOrder。如果有人可以帮我提出任何想法，为什么会发生这种情况会很棒。
iorder header：
std::ostream& operator<<(std::ostream& os, const iOrder& order);
主：
#include <iostream>
#include "GS1Prefix.h"
#include "Order.h"
#define MAXORDERS 100
char menu(std::istream& is);
bool style(std::istream& is, char&);
int main() {
char choice;
int noOrders = 0;
iOrder* order[MAXORDERS];
Prefix prefix("prefixRanges.txt");
std::cout << "Bookstore Order Processor\n"
<< "=========================\n";
// process user input
do {
choice = menu(std::cin);
std::cout << std::endl;
switch (choice) {
case 'P':
{
EAN ean;
if (ean.read(std::cin, prefix)) {
int index = -1, created = false;
for (int i = 0; i < noOrders && index == -1; i++)
if (ean == order[i]->getEAN())
index = i;
if (index == -1)
if (noOrders < MAXORDERS) {
index = noOrders;
order[noOrders++] = new Order(ean);
created = true;
}
else
std::cerr << "No space for more orders!" << std::endl;
if (!order[index]->add(std::cin) && created)
delete order[--noOrders];
}
}
break;
case 'S':
{
EAN ean;
if (ean.read(std::cin, prefix)) {
int index = -1, created = false;
for (int i = 0; i < noOrders && index == -1; i++)
if (ean == order[i]->getEAN())
index = i;
if (index == -1)
if (noOrders < MAXORDERS) {
index = noOrders;
order[noOrders++] = new SpecialOrder(ean, "");
created = true;
}
else
std::cerr << "No space for more orders!" << std::endl;
if (!order[index]->add(std::cin) && created)
delete order[--noOrders];
}
}
break;
case 'A':
{
EAN ean;
if (ean.read(std::cin, prefix)) {
int index = -1;
for (int i = 0; i < noOrders && index == -1; i++)
if (ean == order[i]->getEAN())
index = i;
if (index != -1)
order[index]->add(1);
else
std::cerr << "No order for " << ean << " found!" << std::endl;
}
}
break;
case 'D':
{
EAN ean;
if (ean.read(std::cin, prefix)) {
int index = -1;
for (int i = 0; i < noOrders && index == -1; i++)
if (ean == order[i]->getEAN())
index = i;
if (index != -1)
order[index]->receive(std::cin);
else
std::cerr << "No order for " << ean << " found!" << std::endl;
}
}
break;
case 'F':
{
char s;
if (style(std::cin, s))
for (int i = 0; i < noOrders; i++)
order[i]->getEAN().style(s);
}
break;
case 'V':
std::cout << " EAN Ordered Delivered Instructions\n";
std::cout << "--------------------------------------------------\n";
for (int i = 0; i < noOrders; i++) {
std::cout << *order[i] << std::endl;
}
break;
}
} while (choice != 'Q');
std::cout << "\nSigning off ... " << std::endl;
// deallocate order memory
for (int i = 0; i < noOrders; i++)
delete order[i];
}
// menu prompts for and accepts an option selection from standard input and
// returns the character identifying the selected option
//
char menu(std::istream& is) {
char c;
int ok = false;
std::cout << '\n';
std::cout << "Please select from the following options :\n";
std::cout << " P - Place an order with a publisher\n";
std::cout << " S - Place a special order with a publisher\n";
std::cout << " A - Add one copy to an existing order\n";
std::cout << " D - Record a delivery from a publisher\n";
std::cout << " F - Change output style\n";
std::cout << " V - View status of books on order\n";
std::cout << " Q - Quit\n";
do {
std::cout << " Your selection : ";
c = ' ';
is.get(c);
if (c >= 'a' && c <= 'z')
c -= 'a' - 'A';
if (is.fail()) {
is.clear();
is.ignore(2000, '\n');
std::cerr << " Invalid input. Try again.\n";
}
else if (c == '\n') {
; // no input - try again
}
else if (c != 'P' && c != 'S' && c != 'A' && c != 'D' && c != 'V'
&& c != 'Q' && c != 'F') {
is.ignore(2000, '\n');
std::cerr << " Invalid Character. Try again.\n";
}
else if (is.get() != '\n') {
is.ignore(2000, '\n');
std::cerr << " Trailing Characters. Try Again.\n";
}
else if (c == 'P' || c == 'S' || c == 'A' || c == 'D' || c == 'V'
|| c == 'Q' || c == 'F')
ok = true;
} while (ok == 0);
return c;
}
// style prompts for and accepts the style from input stream is
//
bool style(std::istream& is, char& s) {
bool rc = false, ok = false;
char c;
do {
std::cout << " EAN Style ('-', ' ', '\\n' or '0' to quit) : ";
c = ' ';
is.get(c);
if (is.fail()) {
is.clear();
is.ignore(2000, '\n');
std::cerr << " Invalid input. Try again.\n";
}
else if (c != '-' && c != ' ' && c != '\n' && c != '0') {
is.ignore(2000, '\n');
std::cerr << " Invalid Character. Try again.\n";
}
else if (c == '0') {
if (is.get() != '\n') {
is.ignore(2000, '\n');
std::cerr << " Trailing Characters. Try Again.\n";
}
else
ok = true;
}
else if (c == '\n') {
ok = true;
s = '\0';
rc = true;
}
else if (is.get() != '\n') {
is.ignore(2000, '\n');
std::cerr << " Trailing Characters. Try Again.\n";
}
else if (c == '-' || c == ' ') {
ok = true;
s = c;
rc = true;
}
} while (!ok);
return rc;
}
答案 0 :(得分：1)
您声明并使用此运算符：
std::ostream& operator<<(std::ostream& os, const iOrder& order);
但你没有为它编写任何代码（或者在leats它没有显示代码中）