我的代码出现此错误：
1＆gt; a1ms4.obj：错误LNK2001：未解析的外部符号_name
1＆gt; a1ms4.obj：错误LNK2001：未解析的外部符号_address
1＆gt; a1ms4.obj：错误LNK2001：未解析的外部符号_numbers
所以我的程序有3个文件：
a1ms4.c，contacts.c，contacts.h
当我尝试运行程序时遇到上述错误。
我的节目是这个
a1ms4.c：
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include "contacts.h"
// This source file needs to "know about" the structures you declared
// in the header file before referring to those new types:
// HINT: put the header file name in double quotes so the compiler knows
// to look for it in the same directory/folder as this source file
// #include your contacts header file on the next line:
int main(void)
{
// Declare variables here:
extern struct Name name;
extern struct Address address;
extern struct Numbers numbers;
// Create a variable of type Contact and call it something self-describing like "contact"
// - HINT: Be sure to initialize the values to 0 and empty C strings
extern struct Contact contact;
// Display the title
printf("Contact Management System\n");
printf("-------------------------\n\n");
// Call the Contact function getName to store the values for the Name member
getName(&name);
// Call the Contact function getAddress to store the values for the Address member
getAddress(&address);
// Call the Contact function getNumbers to store the values for the Numbers member
getNumbers(&numbers);
// Display Contact summary details
//havent dont this yet
// Display Completion Message
printf("Structure test for Contact using functions done!\n");
return 0;
}
contacts.c：
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
// This source file needs to "know about" the structures you declared
// in the header file before referring to those new types:
// HINT: put the header file name in double quotes so the compiler knows
// to look for it in the same directory/folder as this source file
// #include your contacts header file on the next line:
#include "contacts.h"
// Get and store from standard input the values for Name
// Put your code here that defines the Contact getName function:
void getName(struct Name *contactName) {
char choice;
printf("Please enter the contact's first name: ");
scanf("%c", (*contactName).firstName);
printf("\n");
printf("Do you want to enter a middle intial(s)? (y or n): ");
scanf("%c", &choice);
printf("\n");
if (choice == 'y') {
printf("Please enter the contact's middle intial(s): ");
scanf("%c", (*contactName).middleInitial);
printf("\n");
}
else {
printf("Please enter the contact's last name: ");
scanf("%c", (*contactName).lastName);
printf("\n");
}
}
// Get and store from standard input the values for Address
// Put your code here that defines the Contact getAddress function:
void getAddress(struct Address *contactAddress){
char choice;
printf("Please enter the contact's street number: ");
scanf("%d", (*contactAddress).streetNumber);
printf("\n");
printf("Please enter the contact's street name: ");
scanf("%c", (*contactAddress).street);
printf("\n");
printf("Do you want to enter an apartment number? (y or n): ");
scanf("%c", &choice);
printf("\n");
if (choice == 'y') {
printf("Please enter the contacts apartment number: ");
scanf("%d", (*contactAddress).apartmentNumber);
printf("\n");
}
printf("Please enter the contact's postal code: ");
scanf("%c", (*contactAddress).postalCode);
printf("\n");
printf("Please enter the contact's city: ");
scanf("%c", (*contactAddress).city);
printf("\n");
}
// Get and store from standard input the values for Numbers
// Put your code here that defines the Contact getNumbers function:
void getNumbers(struct Numbers *contactNumber) {
char choice[5];
printf("Do you want to enter a cell phone number? (y or n) ");
scanf("%c", &choice[0]);
if (choice[0] == 'y') {
printf("\n");
printf("Please enter the contact’s cell phone number: ");
scanf("%d", (*contactNumber).cell);
printf("\n");
}
if (choice[0] == 'n') {
printf("\n");
}
printf("Do you want to enter a home phone number? (y or n) ");
scanf("%c", &choice[1]);
if (choice[1] == 'y') {
printf("\n");
printf("Please enter the contact’s home phone number: ");
scanf("%d", (*contactNumber).home);
printf("\n");
}
if (choice[1] == 'n') {
printf("\n");
}
printf("Do you want to enter a home business number? (y or n) ");
scanf("%c", &choice[3]);
if (choice[2] == 'y') {
printf("\n");
printf("Please enter the contact’s business phone number: ");
scanf("%d", (*contactNumber).home);
printf("\n");
}
if (choice[2] == 'n') {
printf("\n");
}
}
最后：
contacts.h：
// Structure type Name declaration (Milestone 1)
struct Name {
char firstName[31];
char middleInitial[7];
char lastName[36];
};
// Structure type Address declaration
// Place your code here... (from Milestone 1)
struct Address {
char street[41];
int streetNumber[1];
int apartmentNumber[1];
char postalCode[8];
char city [41];
};
// Structure type Numbers declaration
// Place your code here... (from Milestone 1)
struct Numbers {
int cell[21];
int home[21];
int business[21];
};
// Structure type Contact declaration
// Place your code here... (from Milestone 3)
struct Contact{
char name;
char address;
int number;
};
//------------------------------------------------------
// Function Prototypes
//------------------------------------------------------
// ====== Milestone 4 =======
// Get and store from standard input the values for Name
// Place your code here...
void getName(struct Name *);
// Get and store from standard input the values for Address
// Place your code here...
void getAddress(struct Address *);
// Get and store from standard input the values for Numbers
// Place your code here...
void getNumbers(struct Numbers *);
答案 0 :(得分：2)
当你说extern struct Name name;时，它意味着“在其他文件中定义了变量name”。但真的没有！这就是链接器所抱怨的 - 它无法在任何文件中找到变量。
如果您只删除extern，变量将在main内定义，您可以在那里使用它们。