线程1:C中的EXC\u错误访问(代码=1,地址=0x0)
我面临 线程1:EXC\U BAD\U访问代码=1,地址=0x0 每当我尝试将字符串从输入扫描到char*变量时。 我不知道为什么会这样,因为一切似乎都是对的线程1:C中的EXC\u错误访问(代码=1,地址=0x0),c,error-handling,runtime-error,C,Error Handling,Runtime Error,我面临 线程1:EXC\U BAD\U访问代码=1,地址=0x0 每当我尝试将字符串从输入扫描到char*变量时。 我不知道为什么会这样,因为一切似乎都是对的 #include <stdio.h> #include <string.h> #include <time.h> #include <stdlib.h> 日期结构 struct patientData { unsigned int code; char name[11];
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
日期结构
struct patientData {
unsigned int code;
char name[11];
char family[21];
unsigned int age;
char MF;
char disease[11];
unsigned int numOfVisits;
struct date *date1;
struct date *date2;
struct date *date3;
struct patientData *nextPtr;
};
患者数据结构
int isEmpty (struct patientData *sPtr);
void visit ( struct patientData **returned , unsigned int code);
void Insert (struct patientData **sPtr, unsigned int code , char *name , char *family , unsigned int age ,char gender, int tmgh);
void insertDisease (struct patientData **sPtr , char *name , char *family , char *disease );
struct patientData *searchCode (struct patientData **sPtr , unsigned int code, int *returnval);
struct patientData *searchName (struct patientData **sPtr , char *name , char *family);
void searchDate (struct patientData **sPtr , int year , int month , int day );
void delete (struct patientData **sPtr );
void report (struct patientData **sPtr );
功能;
这里主要是问题发生的地方
int main() {
char *choice;
unsigned int code;
char name[11];
char family[21];;
char disease[11];
int searchCodeReturnValue;
unsigned int age;
char gender;
int tmgh;
int year , month , day;
struct patientData *startPtr = NULL;
puts("Enter one of the following options:");
puts("Visit");
puts("InsertDisease");
puts("search");
puts("Delete");
puts("END");
scanf("%s",choice);
while (strcmp(choice, "END") != 0) {
if (strcmp(choice, "Visit") == 0) {
printf("Enter the code:\n");
scanf("%5ui",&code);
struct patientData *a = searchCode(&startPtr,code,&searchCodeReturnValue);
if (searchCodeReturnValue == 1){
visit(&a , code);
}
else if (searchCodeReturnValue == 0){
printf("Enter name:\n");
scanf("%10s",name);
printf("Enter family:\n");
scanf("%20s",family);
printf("Enter age:\n");
scanf("%ui",&age);
printf("Enter gender:\n");
scanf("%c",&gender);
printf("Enter num of last visits:\n");
scanf("%i",&tmgh);
Insert(&startPtr , code , name , family , age , gender , tmgh);
}
}
else if ( strcmp(choice, "InsertDisease")== 0) {
printf("Enter name:\n");
scanf("%10s",name);
printf("Enter family:\n");
scanf("%20s",family);
printf("Enter disease:\n");
scanf("%10s",disease);
struct patientData *namesearch = searchName(&startPtr, name, family);
insertDisease ( &namesearch , name , family , disease );
}
else if (strcmp(choice, "Search")== 0) {
puts("Choose the way you wanna search: \n 1- by code \n 2- by first and last name \n 3- by Date");
int choiceNum;
scanf("%i",&choiceNum);
if (choiceNum == 1) {
printf("Enter the code:\n");
scanf("%5ui",&code);
searchCode(&startPtr, code , &searchCodeReturnValue);
}
else if ( choiceNum == 2){
printf("Enter name:\n");
scanf("%10s",name);
printf("Enter family:\n");
scanf("%20s",family);
searchName(&startPtr ,name , family );
}
else if ( choiceNum == 3){
printf("Enter year:\n");
scanf("%i",&year);
printf("Enter month:\n");
scanf("%i",&month);
printf("Enter day:\n");
scanf("%i",&day);
searchDate(&startPtr , year , month , day);
}
else
puts("Wrong entry");
}
else if (strcmp(choice, "delete")== 0) {
delete(&startPtr);
}
else if (strcmp(choice, "Report") == 0) {
report(&startPtr);
}
else if (strcmp(choice, "END") == 0)
return 0;
else{
puts("wrong!");
return 0;
}
}
return 0;
}
内存没有分配给指针,您正在执行
scanf("%s",choice);
为指针分配内存,然后尝试扫描指针的值
choice = malloc(30); /* Size can be anything of your wish */
因此,您正在访问未初始化的指针,这将导致未定义的行为
一旦使用完这个内存,你需要释放它
free(choice);
您正在解除对无效指针的引用,choice被声明为char指针且从未初始化,您不需要它是char指针,也可以将choice声明为char数组,它包含的最长字符串似乎是INSERTDISE,有13个字符,因此以这种方式声明choice 并将scanf更改为 这样可以防止缓冲区溢出和内存泄漏,如果以后没有适当地释放选项,那么使用malloc也会导致内存泄漏 我看到,您也没有重新扫描choice值,这将使您的循环无限大,您应该将其添加到循环的顶部,并将其移除到循环之外,然后将循环编写为
while (1) {
scanf("%13s", choice);
.
.
/* check the content of choice with strcmp and process the requested command */
.
.
}
在循环中有一个if strcmchoice,END==0返回0;这样就可以结束循环了。真的吗?但我以前使用过这种风格,我从未遇到过这样的错误,为什么它需要内存分配?”包含int main{char*mine;scanf%s,mine;printf%s\n,mine;返回0;}'@user21087 Yes以便将值存储到某个内存位置,您需要为其分配内存。如图所示,可以通过使用malloc执行相同的操作
free(choice);
char choice[14];
scanf("%13s", choice);
while (1) {
scanf("%13s", choice);
.
.
/* check the content of choice with strcmp and process the requested command */
.
.
}