我正在尝试在c中创建具有动态长度/大小的动态char数组(向量)。
这是我的尝试:
#include <stdio.h>
#include <stdlib.h>
void push_back(char **arr, char *element, int *counter) {
if (*counter > 0) {
arr = realloc(arr, *counter * sizeof(char *));
}
arr[*counter] = element;
(*counter)++;
}
int main() {
char **arr = malloc(1 * sizeof(char *));
int counter = 0;
push_back(arr, "element", &counter);
push_back(arr, "element2", &counter);
push_back(arr, "element3", &counter);
push_back(arr, "element4", &counter);
push_back(arr, "element5", &counter);
push_back(arr, "element6", &counter);
for (int i=0; i<counter; i++) {
printf("%s <-\n", (char *)arr[i]);
}
free(arr[i]);
return 0;
}
我从stdout收到以下错误:
realloc(): invalid next size
Aborted
我在做什么错了?
答案 0 :(得分:2)
您需要三重指针***
(wrrrr .....)或只返回重新分配的指针。
char ** push_back(char **arr, char *element, int *counter) {
*counter += 1;
arr = realloc(arr, *counter * sizeof(char *));
arr[*counter - 1] = element;
return arr;
}
int main() {
char **arr = NULL;
int counter = 0;
arr = push_back(arr, "element", &counter);
arr = push_back(arr, "element2", &counter);
arr = push_back(arr, "element3", &counter);
arr = push_back(arr, "element4", &counter);
arr = push_back(arr, "element5", &counter);
arr = push_back(arr, "element6", &counter);
for (int i=0; i<counter; i++) {
printf("%s %d <-\n", arr[i], counter);
}
free(arr);
return 0;
}
您不需要malloc,然后检查计数器的值。 https://godbolt.org/z/xnaxKo
PS Yuo应该始终检查malloc
(和朋友)的结果。