#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct Person {
char *forename;
char *surname;
int age;
};
void change_struct(struct Person *person, char *forename, char *surname,
int age);
void print_struct(struct Person *person);
int main(void)
{
struct Person person1;
person1.forename = malloc((strlen("Max") + 1) * sizeof(char));
if (!person1.forename) {
exit(EXIT_FAILURE);
}
strcpy(person1.forename, "Max");
person1.surname = malloc((strlen("Mustermann") + 1) * sizeof(char));
if (!person1.surname) {
exit(EXIT_FAILURE);
}
strcpy(person1.surname, "Mustermann");
person1.age = 35;
print_struct(&person1);
change_struct(&person1, "Hans", "Bauer", 45);
print_struct(&person1);
free(person1.forename);
free(person1.surname);
exit(EXIT_SUCCESS);
}
void change_struct(struct Person *person, char *forename, char *surname,
int age)
{
person->forename = realloc(person->forename,
(strlen(forename) + 1) * sizeof(char));
if (!person->forename) {
exit(EXIT_FAILURE);
}
strcpy(person->forename, forename);
person->surname = realloc(person->surname,
(strlen(surname) + 1) * sizeof(char));
if (!person->surname) {
exit(EXIT_FAILURE);
}
strcpy(person->surname, surname);
person->age = age;
}
void print_struct(struct Person *person)
{
printf("%s\n", person->forename);
printf("%s\n", person->surname);
printf("%d\n", person->age);
}
指定字符串的指針當在struct
分配一個字符串的指針是明確的行爲,如果我會做在結構
person1.forename = "Max";
person1.surname = "Mustermann";
在main()
最初不是使用malloc()
和strcpy()
?
注:(當然,在這個特定的情況下,我需要也改變change_struct()
的realloc()
電話,因爲它是當realloc()
接收非malloc()
,calloc()
,或realloc()
創建指針未定義行爲)
如果需要動態內存分配,你可以解釋一下爲什麼?
好的,我可以虛心地問downvote的原因嗎? –
我不知道,但我現在認爲''C'是一個相當苛刻的標籤。 (不要試圖開始討論。) –