How to convert single char to long in c

[sreeharibabu]

Ex :
Char x='2';
long out=0;
out=atol(x);

here i want to get out value as 2 but it is not happening
Now out value get 0 . Please suggest as soon as ossible

[stdq]

Hello! I think you could do a cast:

#include <stdio.h>
 
int main( void )
{
    char x = '2';
    long int out = ( long int )x;
 
    printf( "%ld\n", out );
}

However, be careful, because '2' is a character whose decimal value in ASCII is 50, so the output of this code will be 50.

[weaknessforcats]

So just code:

char x=2;
long out=0;
out= x;

A char and a long are both integers so you can assign the char to the long. The compiler won't object because the long is larger than the char. You just can't go the other way without getting a warning from the compiler about possible loss of data.

[Banfa]

The problem is that atol expects a char* not a char. I'm surprised the code you posted even compiles, I am sure it doesn't compile without warnings.

You could just take a pointer to your char

out=atol(&x);

Problem with that is atol doesn't just expect a char* it expects a pointer to a C string, that is a zero terminated array of char which you do not have you have a single char. You could convert it to a string

char buffer[2];
buffer[0] = x;
buffer[1] = '\0';
out=atol(buffer);
 

But personally I find it rather long winded. As long as you are sure there is a digit character in your variable then you can just rely on the language guarantee that digit character values are contiguous (i.e. '1' = '0' + 1 ...)

out= x - '0';