What is the difference between char s[] and char *s?

Question

In C, one can use a string literal in a declaration like this: char s[] = "hello";or like this: char *s = "hello";So what is the difference? I want to know what actually happens in terms of storage duration, both at compile and run time.

Answer 1

char one[] = "abcdefg";

char* two= "abcdefg";

Both achieve the same direct result but operate slightly differently. The first example creates and array of char and then copies the string to that array. The second example creates a pointer to the string.

Answer 2

It helps to know that on one level, array notation is short hand for pointers. When you say a[3]=7, behind the scene, the system is saying *(a+3)=7. What the system is doing is "take the address, stored at location a, add 3 to that (if a is an array of integers, it adds the size of 3 integers), dereference to that location and store the value 7.

The array notation is just easier to use, especially when you start dealing with multi-dimensional arrays. Oddly enough, this actually makes 3[a]=7 valid code, but not so easy to read.

Bottom line, in answer your question, both notations are equivalent.