根据C中的索引构造字符串

Question

When I construct a string like this:

char string[1] = {'a'};
printf("%s", string)

it returns a a4 . Why is there a four at the end? How can I get rid of it?

I choose this method because I need to make a string from character indexes, such as char array[4] = {string[i],string[j],string[k]}; .

Answer 1

Your string should end with terminating char '\\0' You can do it by:

char string[2] = {'a','\0'};

Or:

char string[] = "a";

Answer 2

"strings" in C are essentially arrays of characters ending with the \\0 character (null terminated).
So if you want an array of characters, what you did is fine, but it is not a "string". Dont try to print it as such.
If you would also like to print it or treat it as a "string", then increase it's length by 1, and add a '\\0' char at the end.

Answer 3

The conversion specification %s is used to output strings that is a sequence of characters terminated by a zero character.

The array declared this way

char string[1] = {'a'};

does not contain a string.

So to output its elements you need to specify the exact number of characters you are going to output. For example

printf("%*.*s", 1, 1, string);

Otherwise reserve one more element in the array for the terminating zero and use the conversion specification %s . For example

char string[2] = {'a'};
printf( "%s", string );