The sizeof operator #include "Stdio.h>; Void main () { Char ch= 'one';         Printf ( "%d\n", sizeof (ch));         Printf ( "%d\n", sizeof ( 'one')); } K&R described in the book : In the formula, each CHAR were converted to INT. So why is the result of one and four VC? I understand this is wrong then? The sizeof operator Char in the different systems which are not necessarily the same space occupied by the bar. The sizeof operator Ch is a character variable, sizeof (ch) = sizeof (char) is one. ANSI requirements intger character constant with type int, so sizeof ( 'l') value sizeof (int) of the same value, in your platform, the value of 4. Wchar_t c is the type of different size and char. The sizeof operator Add that in C + +, sizeof ( 'c') value is 1, not C + + int parameters of the characters expansion. [ Closed window ]