循环迭代基于指针的数组？

Question

如果我声明了一个像extern char **seasons这样的外部变量。有关如何编写循环来迭代这个数组的任何提示？假设NULL值是停止条件？

Answer 1

假设你的数组看起来像这样：

const char *data[] = {"This", "is", "an", "array", "of", "strings", NULL};

您可以像这样迭代：

const char** seasons = data;
int i;
for(i = 0; seasons[i] != NULL; ++i) {
    printf("%s ", seasons[i]);
}

Answer 2

#include <stdio.h>
#include <stdlib.h>

extern char **seasons;

int main(){
  int i = 0;
  while(seasons[i] != NULL){
    printf(seasons[i]);
    i++;
  }
  return 0;
}

Answer 3

如果arr是您的数组并且您希望停止在i arr包含NULL的索引for，则标准for (i = 0; arr[i]; i++) dostuff(arr[i]); 循环将如下所示：

{{1}}

Answer 4

以下是3种变体：

extern char **seasons;
size_t i;
for(i = 0; seasons[i]; i++) {
   do_something(seasons[i]);
}

或

extern char **seasons;
char **i;
for(i = seasons; *i ; i++) {
   do_something(*i);
}

或

extern char **seasons;
char **i = seasons;
while(*i) {
   do_something(*i);
   i++;
}