"如何调用和传递字符串数组并在函数内查找该数组的长度"

Question

I am writing a program to check if a string is inside an array of strings. I predefined an array of words before the main method

const char *items[] = {"a","b","c","d"};

then I have a function like

bool isInside(const char *array[], char *s1){
 //which will try to compare all strings from the input array with s1
  int len = sizeof(array)/sizeof(array[0]);
  for (int i =0; i< len ; i++){
   //do string comparasion}
}

It worked before but not sure where I messed up the code now I got two errors and the function is only able to check the first string of the array with s1.

I found out the problem is that now len = 1 always.

one of the errors is

`warning: ‘sizeof’ on array function parameter ‘array’ will return size of ‘const char **’ [-Wsizeof-array-argument]` and the other one is 

isInside(items, words[i]))
      |                               ^~~~~~~~~
      |                               |
      |                               const char **
code.c:63:21: note: expected ‘char *’ but argument is of type ‘const char **’

How can I fix this or call this function so the length is correct and no type warning?

Thanks a lot.

Answer 1

Arrays in C will degrade to pointers when passed as arguments to functions. When they become pointers, their length cannot be retrieved by sizeof<\/code> .

bool isInside(const char **array, int arrayLength, char *s1){
  for (int i =0; i< arrayLength; i++){
     const char* str = array[i];
     if(strcmp(str, s1) == 0){
        return 1;
     }
  }
  return 0;
}