提问人：Hi_Im_Frost 提问时间：4/22/2023 最后编辑：Vlad from MoscowHi_Im_Frost 更新时间：4/22/2023 访问量：49
Strtok 无法正常读取包含多行的字符串 [duplicate]
Strtok not working properly reading a string with multiple lines [duplicate]
问：
所以，我正在使用词法分析器，在所有 flex 恶作剧之后，我得到了这个文本：
ISEP 1252 "ADDRESS"
"Name1" 1253 "INFORMATICA"
"Name2" 1254 "Boilerplate1"
"Name3" 1255 "Boilerplate2"
"Name4" 1256 "Boilerplate3"
"Name5" 1257 "Boilerplate4"
"Name6" 1258 "Boilerplate5"
并将其存储在 中，然后我使用以下命令将每一行和该行的内容分开：yytextstrtok
// get first line
char* line = strtok(yytext, "\n");
// get school name
char* schoolName = strtok(line, " \t");
// get school num students
int schoolNumStudents = atoi(strtok(NULL, " \t"));
// get school address inside the quotes
char* schoolAddress = strtok(NULL, "\"");
strcpy(schools[schoolCount].name, schoolName);
schools[schoolCount].numStudents = schoolNumStudents;
strcpy(schools[schoolCount].address, schoolAddress);
//print school[schoolCount]
printf("Escola: %s\n", schools[schoolCount].name);
printf("Num alunos: %d\n", schools[schoolCount].numStudents);
printf("Morada: %s\n", schools[schoolCount].address);
// get teachers
line = strtok(NULL, "\n");
while (line != NULL) {
char* teacherName = strtok(line, "\"");
int teacherExt = atoi(strtok(NULL, " \t"));
char* teacherDepartment = strtok(NULL, "\"");
schools[schoolCount].numTeachers++;
if(schools[schoolCount].teachers == NULL) {
schools[schoolCount].teachers = (struct Teacher*) malloc(sizeof(struct Teacher));
}
else {
schools[schoolCount].teachers = (struct Teacher*) realloc(schools[schoolCount].teachers, sizeof(struct Teacher) * (schools[schoolCount].numTeachers));
}
printf("Nome: %s\n", teacherName);
printf("Ext: %d\n", teacherExt);
printf("Departamento: %s\n", teacherDepartment);
line = strtok(NULL, "\n");
}
schoolCount++;
这里要看到的是，作为我提供的字符串，第二个返回而不是第二行。我错过了什么吗？yytextstrtok(NULL, "\n")NULL
PS：除了我提供的代码之外，没有任何与C相关的内容，代码块嵌套在lex规则中。
我尝试将 yytext 的内容复制到不同的变量，因为 strtok 会更改变量并且 yytext 保留给 lex，但这没有完成任何事情，我尝试清除 strtok 缓冲区并在第二行中重试 strtok，也没有用。
答：
1赞
Vlad from Moscow
4/22/2023
#1
问题是在调用子字符串行之后strtok
char* line = strtok(yytext, "\n");
// get school name
char* schoolName = strtok(line, " \t");
//..
该函数在数组中保留一个指针。所以下一个电话strtoklinestrtok
line = strtok(NULL, "\n");
引用而不是 。lineyytext
避免该问题的一种方法是计算
例如，存储在 like 中的字符串line
char *pos = yytext;
char* line = strtok( pos, "\n");
size_t n = strlen( line );
//...
并将该值用作数组内的偏移量，以便下次调用数组yytextstrtokyytext
pos += n;
line = strtok( pos, "\n");
//...
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