Size of character ('a') in C/C++
What is the size of character in C and C++ ? As far as I know the size of char is 1 byte in both C and C++.
In C:
#include <stdio.h>
int main()
{
printf("Size of char : %d\n", sizeof(char));
return 0;
}
In C++:
#include <iostream>
int main()
{
std::cout << "Size of char : " << sizeof(char) << "\n";
return 0;
}
No surprises, both of them gives the output : Size of char : 1
Now we know that characters are represented as 'a'
,'b'
,'c'
,'|'
,... So I just modified the above codes to these:
In C:
#include <stdio.h>
int main()
{
char a = 'a';
printf("Size of char : %d\n", sizeof(a));
printf("Size of char : %d\n", sizeof('a'));
return 0;
}
Output:
Size of char : 1
Size of char : 4
In C++:
#include <iostream>
int main()
{
char a = 'a';
std::cout << "Size of char : " << sizeof(a) << "\n";
std::cout << "Size of char : " << sizeof('a') << "\n";
return 0;
}
Output:
Size of char : 1
Size of char : 1
Why the sizeof('a')
returns different values in C and C++?
In C, the type of a character constant like 'a'
is actually an int
, with size of 4 (or some other implementation-dependent value). In C++, the type is char
, with size of 1. This is one of many small differences between the two languages.
As Paul stated, it's because 'a'
is an int
in C but a char
in C++.
I cover that specific difference between C and C++ in something I wrote a few years ago, at: http://david.tribble.com/text/cdiffs.htm