c - 循环以基于指针迭代数组？

Question

如果我声明了一个外部变量，例如extern char **seasons. 有关如何编写循环以遍历此数组的任何提示？假设 NULL 值是停止条件？

Answer 1

假设您的数组如下所示：

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

您可以像这样遍历它：

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

Answer 2

这里有 3 个变种：

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

或者

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

或者

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

Answer 3

如果arr是您的数组并且您想在该索引处停止icontains arr，NULL则标准for循环将如下所示：

for (i = 0; arr[i]; i++)
   dostuff(arr[i]);

Answer 4

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

extern char **seasons;

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