典型的初学者电话簿程序，试图添加对文件功能的读写。它没有编译，因为
1）它无法识别标签ErrorHandler，无论我放在哪里
2）在两个函数中：从不兼容的指针类型[默认启用]传递fprintf的参数2
3）.c文件中包含的文件，打印在两个函数中：期望const char * __restrict__但参数类型为struct pb *
整个代码的代码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct phonebook {
char cFirstName[20];
char cLastName[20];
char PhoNo[20];
} pb;
//function prototypes
void AddContact (pb * );
void DeleteContact (pb * );
void ShowContacts (pb * );
void FindContact (pb * );
void RandContact (pb * );
void FindContact (pb * );
void DeleteAll (pb *);
void Read (pb *);
void Write (pb *);
char FileName[100];
FILE *pRead;
FILE *pWrite;
int counter = 0;
main ()
{
pb *phonebook;
phonebook = (pb*) malloc(sizeof(pb)*1);
int iChoice = 0;
while (iChoice <= 8) {
printf("\n-Choose an option- \n");
printf("\n\t(1)\tAdd Contact");
printf("\n\t(2)\tDelete Contact");
printf("\n\t(3)\tShow All Contacts");
printf("\n\t(4)\tSearch for a Contact");
printf("\n\t(5)\tRandom Contact");
printf("\n\t(6)\tDelete All Contacts");
printf("\n\n\t(7)\tWrite contacts to file");
printf("\n\t(8)\tRead contacts from file");
printf("\n\n\t(9)\tExit\n\n\t");
scanf("%d", &iChoice);
if (iChoice == 1) {
AddContact(phonebook);
}
if (iChoice == 2) {
DeleteContact (phonebook);
}
if (iChoice == 3) {
ShowContacts(phonebook);
}
if (iChoice == 4) {
FindContact(phonebook);
}
if (iChoice == 5) {
RandContact(phonebook);
}
if (iChoice == 6) {
DeleteAll(phonebook);
}
if (iChoice == 7) {
Write(phonebook);
}
if (iChoice == 8) {
Read(phonebook);
}
if (iChoice == 9) {
free(phonebook);
return 0;
}
} //end while
} //end main
//function definitions
//add contact
void AddContact (pb * phonebook)
{
counter++; //counter incremented for each entry
realloc(phonebook, sizeof(pb)); //realloc with every new contact
printf("\nFirst Name: ");
scanf("%s", phonebook[counter-1].cFirstName);
printf("Last Name: ");
scanf("%s", phonebook[counter-1].cLastName);
printf("Phone Number: ");
scanf("%s", phonebook[counter-1].PhoNo);
printf("\n\tContact added\n");
}
//delete contact
void DeleteContact (pb * phonebook)
{
int x = 0;
char scrapcFirstName[20]; //strings for deleting original strings
char scrapcLastName[20];
char nullStr[20] = {"\0"};
printf("\nFirst name: ");
scanf("%s", scrapcFirstName);
printf("Last name: ");
scanf("%s", scrapcLastName);
//compare strings
for (x = 0; x < counter; x++) {
if (strcmp(scrapcFirstName, phonebook[x].cFirstName) == 0) {
for (x = 0; x < counter; x++) {
if (strcmp(scrapcLastName, phonebook[x].cLastName) == 0) {
strcpy(phonebook[x].cFirstName, nullStr);
strcpy(phonebook[x].cLastName, nullStr);
strcpy(phonebook[x].PhoNo, nullStr);
}//end if
else {
printf("Invalid Input");
}
}//end for
}//end if
}// end for
counter--; // Contact deleted, update counter
printf("Contact Deleted\n");
}
//show phonebook
void ShowContacts (pb * phonebook)
{
int x = 0;
printf("\nPhonebook:\n\n ");
for( x = 0; x < counter; x++) {
printf("\n(%d)\n", x+1);
printf("Name: %s %s\n", phonebook[x].cFirstName, phonebook[x].cLastName);
printf("Number: %s\n", phonebook[x].PhoNo);
} //end for
}
//Find a specific contact
void FindContact (pb * phonebook)
{
int x = 0;
char TempFirstName[20];
char TempLastName[20];
printf("\nWho are you looking for?");
printf("\n\nFirst Name: ");
scanf("%s", TempFirstName);
printf("Last Name: ");
scanf("%s", TempLastName);
for (x = 0; x < counter; x++) {
if (strcmp(TempFirstName, phonebook[x].cFirstName) == 0) {
if (strcmp(TempLastName, phonebook[x].cLastName) == 0) {
printf("\n%s %s \n%s\n", phonebook[x].cFirstName,
phonebook[x].cLastName,
phonebook[x].PhoNo);
}
}
}
}
//show a random contact
void RandContact (pb * phonebook)
{
int iRand = 0;
srand(time(NULL));
iRand = rand() % counter;
int x = iRand;
printf("\n%s %s\n", phonebook[x].cFirstName, phonebook[x].cLastName);
printf("%s\n", phonebook[x].PhoNo);
}
//delete all
void DeleteAll (pb * phonebook)
{
int x = 0;
char nullStr[20] = {'\0'};
for ( x = 0; x < counter; x++) {
strcpy(phonebook[x].cFirstName, nullStr);
strcpy(phonebook[x].cLastName, nullStr);
strcpy(phonebook[x].PhoNo, nullStr);
--counter;
}
printf("Contacts have been wiped.\n");
}
void Read(pb * phonebook)
{
FILE *pRead;
char name[256];
printf("File to read:");
gets(name);
pWrite=fopen(name,"a");
if(pWrite != NULL) {
printf("Contact List");
while(!feof(pRead)) {
fprintf(pRead, phonebook,sizeof (struct phonebook));
if (!feof(pRead)) {
fprintf(pRead, phonebook,sizeof (struct phonebook));
}
}
}
else {
goto ErrorHandler;
}
exit(EXIT_SUCCESS);
ErrorHandler:
perror("The folling error occured:");
exit(EXIT_FAILURE);
}
void Write(pb * phonebook)
{
FILE *pWrite;
char name[256];
printf("File to write:");
gets(name);
pWrite=fopen(name,"a");
if(pWrite != NULL) {
fprintf(pWrite, phonebook,sizeof (struct phonebook));
fclose(pWrite);
}
else {
goto ErrorHandler;
}
exit(EXIT_SUCCESS);
ErrorHandler:
perror("The folling error occured:");
exit(EXIT_FAILURE);
}
答案 0 :(得分：0)
Q1。从C标准第6.8.6.1节开始：
goto语句中的标识符应命名位于封闭函数中某处的标签。
goto语句不得从具有可变修改类型的标识符范围之外跳转到该标识符范围内。
goto语句导致无条件跳转到封闭函数中以命名标签为前缀的语句。
你的教授得到的是你需要在每个函数中放置goto到底部的一个部分，该部分处理相对于该函数的清理（关闭文件等），然后执行{return 1}}。良好使用goto（和坏的）的示例如下：Examples of good gotos in C or C++
Q2。这意味着printf中的格式说明符与传递的参数类型不匹配。在这种情况下，你正在做：
fprintf(pRead, phonebook, sizeof (struct phonebook));
fprintf将char *作为字符串指定格式。你永远不应该直接将结构传递给它（想象如果你使用fprintf并且电话簿条目有%签到会发生什么。）
在这种情况下，您希望将固定大小的对象写入文件，而不是NULL终止的字符串。因此，您应该在任何情况下使用fwrite而不是fprintf，例如
fwrite(phonebook, sizeof (struct phonebook), 1, pRead);
您还应该考虑错误检查以及pRead是否是您要撰写的FILE *的好名称。
Q3。见Q2。
答案 1 :(得分：-1)
您应该将电话簿转换为char *：
fprintf(pWrite, (char*)phonebook,sizeof (struct phonebook));
goto不能在不同的功能之间跳转 你需要在每个函数中都有一个“ErrorHandler”标记。
也许更好的解决方案是Makro。