小贝子编程

C-读取文件并打印到文件后获取无效字符，可能是缓冲区溢出



我有一个文件，里面有名字、姓氏、id和电子邮件，按随机顺序排列。我必须组织这些数据，按照组织的方式写入结构和输出文件。可能有多个名称和姓氏。以下是disordered.txt:的示例

abc@gmail.com Andee Kenny SMITH 1234
ADAM ADAM abc@gmail.com Andeee 21654
Anderea abc@gmail.com SAMMY 3524654
abc@gmail.com Andi BROWN 1245
Andie abc@gmail.com KNOWY 2485
Andra abc@gmail.com BRUCE 52445
Andrea abc@gmail.com 246574 DENNIS
2154 Andreana abc@gmail.com CHASE
Andree 21524 SIERRRA abc@gmail.com
Andrei 154 MONDY abc@gmail.com
4564765 Andria LE BARC abc@gmail.com
78 Andriana abc@gmail.com WALLS

我的代码适用于这12个人，但如果我大量复制粘贴它或添加新的人，在33个人之后，它会以重复的方式在姓名前面打印无效字符。

以下是：organized.txt 的屏幕截图

我更喜欢在我的结构中使用字符指针。

这是我的代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define TRUE 1
#define WORD_SIZE 30
#define NAME 1
#define SURNAME 2
#define EMAIL 3
#define ID 4
typedef struct ppl {
char* name;
char* surname;
char* eMail;
int id;
} PEOPLE;
int whichDataType (char* buffer);
void writeData (PEOPLE* person, char* buffer, int whichData, int* nameTimes, int* surnameTimes, int personNumber);  
void printData (PEOPLE* person, FILE* sptr, int personNumber);
int main (void) {
FILE* fptr = NULL;
fptr = fopen("disorganized.txt", "r");
if (fptr == NULL) {
printf ("Disorganized file couldn't openn");
printf ("Exiting the programn");
exit(TRUE);
}
FILE* sptr = NULL;
sptr = fopen("organized.txt", "w");
if (sptr == NULL) {
printf ("Organized file couldn't openn");
printf ("Exiting the programn");
exit(TRUE);
}
int whichData;
int personNumber = 0;
int* nameTimes;
int* surnameTimes;
int forOnce = 0;
char* buffer;
int* buffer2;
PEOPLE* person;
person = (PEOPLE*) malloc (sizeof(PEOPLE));     
buffer = (char*) malloc ( WORD_SIZE * sizeof(char));
nameTimes = (int*) malloc ( sizeof(int));
surnameTimes = (int*) malloc (sizeof(int));
*nameTimes = 0;
*surnameTimes = 0;
//gets word 'till EOF
while ((fscanf(fptr, "%s", buffer)) == 1) {
if (personNumber != 0) {
//creates new structure
person = (PEOPLE*) realloc (person, personNumber * sizeof(PEOPLE));
}
//looks what type of data
whichData = whichDataType(buffer);
//allocates inside of structures and writes
writeData(person, buffer, whichData, nameTimes, surnameTimes, personNumber);
buffer2 = (int*) malloc (sizeof(int));
*buffer2 = fgetc(fptr); //checks what's coming next
if (*buffer2 == 'n') {
if (forOnce == 0) {
//to open a place for next person in my structure pointer, since personNumber = 0; increasing it with 1 and reallocating it with 1*sizeof(PEOPLE) would be the allocating memory for person 1 twice.
personNumber = personNumber + 2;
free(buffer2);
free(buffer);
buffer = (char*) malloc ( WORD_SIZE * sizeof(char));
*nameTimes = 0;
*surnameTimes = 0;
++forOnce;
}
else {
++personNumber;
free(buffer2);
free(buffer);
buffer = (char*) malloc ( WORD_SIZE * sizeof(char));
*nameTimes = 0;
*surnameTimes = 0;
}
}
else if (*buffer2 == ' ' || *buffer2 == 't') {
free(buffer2);
free(buffer);
buffer = (char*) malloc ( WORD_SIZE * sizeof(char));
}
}
--personNumber; //my algorithm increases it 1 more time which is redundant
printData (person, sptr, personNumber);
int i;
for (i = 0; i<personNumber; ++i) {
free((person+i)->name);
free((person+i)->surname);
free((person+i)->eMail);
}
free(person);
free(buffer);
free(buffer2);
free(nameTimes);
free(surnameTimes);
fclose(fptr);
fclose(sptr);
return 0;
}
int whichDataType (char* buffer) {
if (buffer[0] >= 'A' && buffer[0] <= 'Z') {
if (buffer[1] >= 'a' && buffer[1] <= 'z') {
return NAME;
}
else if (buffer[1] >= 'A' && buffer[1] <= 'Z') {
return SURNAME;
}
}
else if (buffer[0] >= 'a' && buffer[0] <= 'z') {
return EMAIL;
}
else if (buffer[0] >= '0' && buffer[0] <= '9') {
return ID;
}
} 
void writeData (PEOPLE* person, char* buffer, int whichData, int* nameTimes, int* surnameTimes, int personNumber) {
if (personNumber != 0) {
--personNumber;
}
switch (whichData) {
case NAME:
if (*nameTimes == 0) {
(person + personNumber)->name = (char*) malloc ( WORD_SIZE * sizeof(char));
++(*nameTimes);
}
break;
case SURNAME:
if (*surnameTimes == 0) {
(person+personNumber)->surname = (char*) malloc ( WORD_SIZE * sizeof(char));
++(*surnameTimes);
}
break;
case EMAIL:
(person + personNumber)->eMail = (char*) malloc ( WORD_SIZE * sizeof(char));
break;
}
char space[2];
strcpy(space, " ");
switch (whichData) {
case NAME:
if (*nameTimes == 0) {
strcpy( (person+personNumber)->name, buffer);
}
else {
strcat ( (person+personNumber)->name, space);
strcat( (person+personNumber)->name, buffer);
}
break;
case SURNAME:
if (*surnameTimes == 0) {
strcpy ( (person+personNumber)->surname, buffer);
}
else {
strcat( (person + personNumber)->surname, space);
strcat( (person + personNumber)->surname, buffer);
}
break;
case EMAIL:
strcpy( (person + personNumber)->eMail, buffer);
break;
case ID:
(person+personNumber)->id = atoi(buffer);
break;
}
}
void printData (PEOPLE* person, FILE* sptr, int personNumber) {
fprintf(sptr, "-------------------------------------------------------------------------------------------------------------------------------------------------------------------");
fprintf(sptr, "n|%30stt", "***NAME***");
fprintf(sptr, "|%30stt", "***SURNAME***");
fprintf(sptr, "|%30stt", "***E-MAIL***");
fprintf(sptr, "|%30st|n", "***ID NUMBER***");
fprintf(sptr, "-------------------------------------------------------------------------------------------------------------------------------------------------------------------");
int i;
for (i = 0; i<personNumber; ++i) {
fprintf(sptr, "n|%d%30stt", i, (person+i)->name);
fprintf(sptr, "|%30stt", (person+i)->surname);
fprintf(sptr, "|%30stt", (person+i)->eMail);
fprintf(sptr, "|%30dt|n", (person+i)->id);
fprintf(sptr, "-------------------------------------------------------------------------------------------------------------------------------------------------------------------");
}
}

我尝试malloc每个新结构及其内部，在完成对它们的工作后释放缓冲区，并将它们再次分配给下一个。如果一个人有多个名字或姓氏，我会将其名字或姓氏分配一次，并将strcpy我的缓冲区分配到适当的位置。如果我再次使用writeData函数为同一个人输入姓名，我会传递分配的内存，因为我已经这样做了。然后，我基本上将我的新缓冲区(名称或姓氏)连接到旧缓冲区。

我的问题是，为什么我会得到这些无效字符，我在哪里犯了错误，我该如何防止它？

我看到了问题并解决了它。这是一个算法问题。当程序为名字分配内存时，当涉及到第二个名字时，不要再为人名字符串分配内存，不要丢失第一个名字，我增加了nameTimes一次。然后在第二个开关，由于它是第一个名称，它应该已经输入if (*nameTimes == 0)部分到strcpy。但由于我在分配时已经增加了它，所以它从来没有进入那个部分，它总是使用strcat来复制字符串。但由于没有字符串可连接，所以出现了问题。我将该部分的条件更改为if (*nameTimes == 1)。然后出现了第二个问题，那就是它只是打印姓氏，只是因为我没有再次增加它，所以它卡在了strcpy部分。所以我在strcpy之后再次增加了它。姓氏也是如此。由于@Barmar和@user3629249，我还改进了代码。

|新代码|

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define WORD_SIZE 30
#define NAME 1
#define SURNAME 2
#define EMAIL 3
#define ID 4

typedef struct ppl {
char* name;
char* surname;
char* eMail;
int id;
} PEOPLE;
int whichDataType (char* buffer);
void writeData (PEOPLE* person, char* buffer, int whichData, int* nameTimes, int* surnameTimes, int personNumber);  
void printData (PEOPLE* person, FILE* sptr, int personNumber);
int main (void) {
FILE* fptr = NULL;
fptr = fopen("disorganized.txt", "r");
if (fptr == NULL) {
perror("Error: ");
exit( EXIT_FAILURE );
}
FILE* sptr = NULL;
sptr = fopen("organized.txt", "w");
if (sptr == NULL) {
perror("Error: ");
exit( EXIT_FAILURE );
}

int whichData;
int personNumber = 0;
int nameTimes = 0;
int surnameTimes = 0;
int forOnce = 0;
char* buffer = NULL;
int* buffer2 = NULL;
PEOPLE* person = NULL;
PEOPLE* realloctemp = NULL;

person = malloc (sizeof(PEOPLE));
if ( person == NULL ) {
perror("Error, malloc failed for person. ");
exit ( EXIT_FAILURE );
}
buffer = malloc ( WORD_SIZE * sizeof(char));
if ( buffer == NULL ) {
perror("Error, malloc failed for buffer. ");
exit ( EXIT_FAILURE );
}

while ((fscanf(fptr, "%29s", buffer)) == 1) {
if (personNumber != 0) {
realloctemp = realloc (person, personNumber * sizeof(PEOPLE));
if ( realloctemp == NULL ) {
perror("Error, reallocating. ");
exit ( EXIT_FAILURE );
}
else {
person = realloctemp;
}
}
whichData = whichDataType(buffer);
writeData(person, buffer, whichData, &nameTimes, &surnameTimes, personNumber);
buffer2 = malloc (sizeof(int));
if ( buffer2 == NULL ) {
perror("Error, malloc failed for buffer2. ");
exit ( EXIT_FAILURE );
}
else {
*buffer2 = fgetc(fptr);
}
if (*buffer2 == 'n') {
if (forOnce == 0) {
personNumber = personNumber + 2;
free(buffer2);
free(buffer);
buffer = malloc ( WORD_SIZE * sizeof(char));
if ( buffer == NULL ) {
perror("Error*, malloc failed for buffer. ");
exit ( EXIT_FAILURE );
}
nameTimes = 0;
surnameTimes = 0;
++forOnce;
}
else {
++personNumber;
free(buffer2);
free(buffer);
buffer = malloc ( WORD_SIZE * sizeof(char));
if ( buffer == NULL ) {
perror("Error**, malloc failed for buffer. ");
exit ( EXIT_FAILURE );
}
nameTimes = 0;
surnameTimes = 0;
}
}
else if (*buffer2 == ' ' || *buffer2 == 't') {
free(buffer2);
free(buffer);
buffer = malloc ( WORD_SIZE * sizeof(char));
if ( buffer == NULL ) {
perror("Error***, malloc failed for buffer. ");
exit ( EXIT_FAILURE );
}
}
}
--personNumber;
printData (person, sptr, personNumber);
int i;
for (i = 0; i<personNumber; ++i) {
free((person+i)->name);
free((person+i)->surname);
free((person+i)->eMail);
}
free(person);
free(buffer);
free(buffer2);
fclose(fptr);
fclose(sptr);
return EXIT_SUCCESS;
}
int whichDataType (char* buffer) {
if (buffer[0] >= 'A' && buffer[0] <= 'Z') {
if (buffer[1] >= 'a' && buffer[1] <= 'z') {
return NAME;
}
else if (buffer[1] >= 'A' && buffer[1] <= 'Z') {
return SURNAME;
}
}
else if (buffer[0] >= 'a' && buffer[0] <= 'z') {
return EMAIL;
}
else if (buffer[0] >= '0' && buffer[0] <= '9') {
return ID;
}
else {
perror("Invalid data type. ");
exit( EXIT_FAILURE );
}
} 
void writeData (PEOPLE* person, char* buffer, int whichData, int* nameTimes, int* surnameTimes, int personNumber) {
if (personNumber != 0) {
--personNumber;
}
switch (whichData) {
case NAME:
if (*nameTimes == 0) {
(person + personNumber)->name = malloc ( WORD_SIZE * sizeof(char));
if ( (person+personNumber)->name == NULL ) {
perror("Error. malloc failed for (person+personNumber)->name");
exit ( EXIT_FAILURE );
}
++(*nameTimes);
}
break;
case SURNAME:
if (*surnameTimes == 0) {
(person+personNumber)->surname = malloc ( WORD_SIZE * sizeof(char));
if ( (person+personNumber)->surname == NULL ) {
perror("Error. malloc failed for (person+personNumber)->surname");
exit ( EXIT_FAILURE );
}
++(*surnameTimes);
}
break;
case EMAIL:
(person + personNumber)->eMail = malloc ( WORD_SIZE * sizeof(char));
if ( (person+personNumber)->eMail == NULL ) {
perror("Error. malloc failed for (person+personNumber)->eMail");
exit ( EXIT_FAILURE );
}
break;
}

char space[2];
strcpy(space, " ");

switch (whichData) {
case NAME:
if (*nameTimes == 1) {
strcpy( (person+personNumber)->name, buffer);
++(*nameTimes);
}
else if (*nameTimes>1) {
strcat ( (person+personNumber)->name, space);
strcat( (person+personNumber)->name, buffer);
}
else {
perror("Error, invalid nameTimes value. ");
exit ( EXIT_FAILURE );
}
break;
case SURNAME:
if (*surnameTimes == 1) {
strcpy ( (person+personNumber)->surname, buffer);
++(*surnameTimes);
}
else if (*surnameTimes>1) {

strcat( (person + personNumber)->surname, space);
strcat( (person + personNumber)->surname, buffer);
}
else {
perror("Error, invalid surnameTimes value. ");
exit ( EXIT_FAILURE );
}
break;
case EMAIL:
strcpy( (person + personNumber)->eMail, buffer);
break;
case ID:
(person+personNumber)->id = atoi(buffer);
break;
}

}
void printData (PEOPLE* person, FILE* sptr, int personNumber) {
fprintf(sptr, "-------------------------------------------------------------------------------------------------------------------------------------------------------------------");
fprintf(sptr, "n|%30stt", "***NAME***");
fprintf(sptr, "|%30stt", "***SURNAME***");
fprintf(sptr, "|%30stt", "***E-MAIL***");
fprintf(sptr, "|%30st|n", "***ID NUMBER***");
fprintf(sptr, "-------------------------------------------------------------------------------------------------------------------------------------------------------------------");
int i;
for (i = 0; i<personNumber; ++i) {
fprintf(sptr, "n|%d%30stt", i+1, (person+i)->name);
fprintf(sptr, "|%30stt", (person+i)->surname);
fprintf(sptr, "|%30stt", (person+i)->eMail);
fprintf(sptr, "|%30dt|n", (person+i)->id);
fprintf(sptr, "-------------------------------------------------------------------------------------------------------------------------------------------------------------------");
}
}

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