Null-Terminated string

Question

Which of the following are null-terminated string?

char *str1 = "This is a string.";
char *str2 = "This is a string.\0";
char str3[] = "This is a string.";
const char *str4 = "This is a string.";
const char *str5 = "This is a string.\0";
const char str6[] = "This is a string.";

Answer 1

• All : a string literal is a null terminated string
• str2 and str5 have the particularity of being doubly null-terminated strings

Also :

• char *str1 should be const char *str1
• char *str2 should be const char *str2

Answer 2

They are all null-terminated (str2 and str5 are actually doubly-null-terminated) because using double quotes is a shorthand for a null-terminated char array.

So this:

"Hello"

Is actually this:

{'H', 'e', 'l', 'l', 'o', '\0'}

Variables pointing to string literals such as these should be declared as const.

Answer 3

All. C compiler auto aggregates string with a terminate '\0', then store it in a char[] or refer to it by char *;