Strings

Strings are arrays of char. Their size is the number of characters + 1 (the NULL (\0) character).

Code example:

char c[6]; // 6 is the minimum size for "HELLO"

c[0] = 'H';
c[1] = 'E';
c[2] = 'L';
c[3] = 'L';
c[4] = 'O';
c[5] = '\0'; // NULL

printf("%s", c); // uses a NULL character to know when to stop printing the array
// without NULL it would print memory contents past the end of the string

char c[6] = { 'H', 'E', 'L', 'L', 'O', '/0' }; // includes NULL

char c[6] = "HELLO"; // adds NULL implicitly
c = "SOMETHING" // ERROR! Arrays cannot be modified like this. strcpy should be used

char c[] = "HELLO"; // array will have a size of 6 implicitly

Memory

Arrays and pointers are different:

char c[20] = "Hello"; // stored on the STACK segment
c[0] = 'A'; // OK

char *d = "Hello"; // stored in the STATIC memory segment
d[0] = 'A'; // ERROR

If a function expects char *a as an argument, how can it know if it’ll be a pointer or an array?

← Pointers

Dynamic Memory →