/* Example in unions */
#include <stdio.h> // standard header file
#include <ctype.h> // for atoi function
#include <stdlib.h> // for malloc function
#include <assert.h> // for assert macro
#define MAX 512 // for fgets()
typedef enum {National, Alien} PERSON_KIND;
typedef struct date {
int month;
int day;
int year;
} DATE;
typedef struct {
char countryOfOrigin[30];
DATE * dateOfEntry; // so you get comfortable with pointers
enum { Worker, Tourist, Student} visaStatus;
char portOfEntry[30];
} ALIEN;
typedef struct {
char placeOfBirth[30];
char ssn[20];
} CITIZEN;
typedef union {
ALIEN alien;
CITIZEN citizen;
} PERSON_INFO;
typedef struct person {
char name[30];
DATE * dateOfBirth; // just to make it interesting
PERSON_KIND personKind;
PERSON_INFO info;
} PERSON;
void fillInfo(PERSON *);
void printInfo(const PERSON *);
int main() {
printf("sizeof(int) is %u\n", (unsigned) sizeof(int) );
printf("sizeof(PERSON_KIND) is %u\n", (unsigned) sizeof(PERSON_KIND) );
printf("sizeof(DATE) is %u\n", (unsigned) sizeof(DATE) );
printf("sizeof(ALIEN) is %u\n", (unsigned) sizeof(ALIEN) );
printf("sizeof(CITIZEN) is %u\n", (unsigned) sizeof(CITIZEN) );
printf("sizeof(PERSON_INFO) is %u\n", (unsigned) sizeof(PERSON_INFO) );
printf("sizeof(PERSON) is %u\n", (unsigned) sizeof(PERSON) );
/* fillInfo(&p1);
printf("\nThe infomation you entered is given below:\n");
printInfo(&p1);
fillInfo(&p2);
printf("\nThe infomation you entered is given below:\n");
printInfo(&p2); */
return 0;
}
/* void fillInfo(PERSON *p) {
char buf[MAX], i;
printf("Please enter the person's name: ");
printf("Please enter the birth month: ");
printf("Please enter the birth date: ");
printf("Please enter the birth year: ");
printf("Please enter 1 if the person is a National or 2\n");
printf("if the person is an alien: ");
// get the value from the user and store it as an integer in i
if (i == 1) p -> personKind = National;
else p -> personKind = Alien;
if (p -> personKind == National) {
printf("Please enter the place of birth: ");
printf("Please enter the ssn: ");
}
if (p -> personKind == Alien) {
printf("Please enter the country of origin: ");
printf("Please enter the month the person entered this country: ");
printf("Please enter the day of the month the person entered this country: ");
printf("Please enter the year the person entered this country: ");
printf("Please enter the person's immigration status : \n");
printf("\t1 for Worker:\n");
printf("\t2 for Tourist:\n");
printf("\t3 for Student: \n");
fgets(buf, MAX, stdin);
i = atoi(buf);
switch (i) {
case 1 :
p -> info.alien.visaStatus = Worker;
break;
case 2 :
p -> info.alien.visaStatus = Tourist;
break;
case 3 :
p -> info.alien.visaStatus = Student;
}
printf("Please enter the port of entry: ");
}
}
void printInfo(const PERSON *p) {
printf("Name: %s\n", p -> name);
printf("Date of Birth: %2d/%2d/%4d\n", );
printf("Status: ");
if ( p -> personKind == National) printf("National\n");
else printf("Alien\n");
if ( p -> personKind == National) {
printf("Place of birth: %s\n", );
printf("SSN: %s\n", );
}
if ( p -> personKind == Alien) {
printf("Country of origin: %s\n", );
printf("Date of Entry: %2d/%2d/%4d\n", );
printf("Immigration status: ");
switch (p -> info.alien.visaStatus) {
case Worker :
printf("Worker\n");
break;
case Tourist :
printf("Tourist\n");
break;
case Student :
printf("Student\n");
}
printf("Port of Entry: %s\n\n", );
}
} // print_info */
预期输出：
sizeof(int) is 4
sizeof(PERSON_KIND) is 4
sizeof(DATE) is 12
sizeof(ALIEN) is 80
sizeof(CITIZEN) is 50
sizeof(PERSON_INFO) is 80
sizeof(PERSON) is 128
Please enter the person's name: John Doe
Please enter the birth month: 10
Please enter the birth date: 31
Please enter the birth year: 1989
Please enter 1 if the person is a National or 2
if the person is an alien: 1
Please enter the place of birth: Worcester
Please enter the ssn: 012345678
The infomation you entered is given below:
Name: John Doe
Date of Birth: 10/31/1989
Status: National
Place of birth: Worcester
SSN: 012345678
Please enter the person's name: Jane Smith
Please enter the birth month: 2
Please enter the birth date: 20
Please enter the birth year: 1970
Please enter 1 if the person is a National or 2
if the person is an alien: 2
Please enter the country of origin: Libya
Please enter the month the person entered this country: 10
Please enter the day of the month the person entered this country: 23
Please enter the year the person entered this country: 2009
Please enter the person's immigration status :
1 for Worker:
2 for Tourist:
3 for Student:
1
Please enter the port of entry: New York
The infomation you entered is given below:
Name: Jane Smith
Date of Birth: 2/20/1970
Status: Alien
Country of origin: Libya
Date of Entry: 10/23/2009
Immigration status: Worker
Port of Entry: New York
取消注释所有注释代码时的编译器错误：
Example_union.c: In function ‘main’:
Example_union.c:56:12: error: ‘p1’ undeclared (first use in this function)
Example_union.c:56:12: note: each undeclared identifier is reported only once for each function it appears in
Example_union.c:60:12: error: ‘p2’ undeclared (first use in this function)
Example_union.c:62:20: error: expected expression before ‘/’ token
Example_union.c: In function ‘printInfo’:
Example_union.c:132:41: error: expected expression before ‘)’ token
Example_union.c:139:34: error: expected expression before ‘)’ token
Example_union.c:140:23: error: expected expression before ‘)’ token
Example_union.c:144:37: error: expected expression before ‘)’ token
Example_union.c:146:43: error: expected expression before ‘)’ token
Example_union.c:160:35: error: expected expression before ‘)’ token
Example_union.c:65:1: warning: control reaches end of non-void function [-Wreturn-type]
我不熟悉工会……因为我只熟悉结构。想知道如何完成上面的代码/联合示例，以便产生正确的输出，如上所示。我还列出了未完成代码的当前编译器错误。希望你能帮忙，因为我急需。谢谢。