Thread: Char to int!!

Hi
Let's say i have
char c = '2';
do anyone know how to get that 2 and store it in an int so that we have int x = 2 ??

x = atoi(c);

atoi() takes char *, not char. Which is to say, it takes a string.

Code:

int x=c-'0';

or if you really want to use atoi:

Code:

char tmp[]={c,0};
int x=atoi(tmp);

Ya but root4 can you explain why c-'0' is 2?? it just an operation on chars , why it gives an int??

A 'char' is an integer too but of a different size:
by definition sizeof(char)=1 byte, and on 32-bit systems, sizeof(int)=4 bytes.
Depending on the compiler, a char is signed or not.

I forgot to say a character is simply stored as a value, which interpretation
depends on the current 'encoding' (e.g. the value 65 means 'A' using the
ASCII encoding), hence c-'0'='2'-'0'=value for symbol '2' - value for symbol '0'=50-48=2
(digits and letters codes are sorted as expected, fortunately)

And are we supposed to know these values of the char 0 and 2 ?? because I'm a beginner And i didn't see these kind of things in class..

You don't have to know them, I gave the values above to explain why it works,
simply remember that if c is the code of a digit ('0'..'9') in any ASCII-compatible
encoding, then simply substract '0' to get the corresponding integer.

Ok , thanks a lot