return value of printf in c?

Question

int main()
{
        int x = 10, y;
        y = printf("x = %d\n", x);
        printf("y = %d\n", y);
        return 0;
}

output:
x = 10
y = 7

I know printf returns the number of character when we print string. But why is returning 7 when printing 10. what is the return value of printf when it prints int ?

Possible Duplicate: Return value of printf() function in C

Answer 1

Like you said, "printf returns the number of character when we print string".

" x = 10\\n " has 7 chars. (Namely, these: 'x',' ','=',' ','1','0','\\n' ).

Thus, y is set to 7.

Answer 2

Read: int printf ( const char * format, ... );

On success, the total number of characters written is returned.

for x = 10 in your code first printf:

printf("x = %d\n", x);

prints seven chars x = 10\\n , and return 7 that is received in y :

    x = 10\n
    1234567 
     ^ ^  ^- new line char \n
     | |--spaces   

remember \\n (new line)is single char, and space is single char.

Answer 3

The length of the string:

"x = 10\n"

(not including double quotes) is 7 characters. That is what is being stored in y . The white spaces and '\\n' are also each just 1 character.

Answer 4

"x = %d\\n" Of course there are 7 characters. Notice there are 2 "space",1 "%" and 1"d", remember "\\n" is a whole . You can try other sentences. such as z = printf("x = %d,asd\\n",x); or sth. like that. The answer is 11. I think such questions can be done by just one more line codes .