Hexadecimal function problem

Hi everyone,

I am working on a little function that calculates a decimal value of
a hexadecimal input, when I run the program it gives me negative
numbers and I cann't figure out why it doing so:

can anyone have look at my code and have look what I am getting wrong ?

here is the code with test main:

Code:

code

void main(void)
{
       int X;
       int Y;

       printf("enter  a hex value :  ");
       scanf("%x", & Y);
      
       X = Convert( Y); 
       printf(" corresponding decimal value is %d\n",  X);
}    


int Convert(char val )
{
      
   if ((val >= 0 ) && (val <= 9))
   {
       val = (int)val - 0; 
       return val ;
   }
   else if(val=='A'||val=='B'|| val=='C'||val=='D'||val=='E'||val=='F' )
   {   
       val = (int)val - (int)('A') + 10;
       return val; 
   }
         
}

Thanks in advance

You've over complicated things....... Have a look at this version:

Code:

#include <stdio.h>

int main(void)
{
	long int X;

	printf("Enter a hex value : ");
	if (scanf("%x", &X) == 1)
		printf ("You entered %d\n", X);
	return 0;
}

Hi Hammer,

I want definitely to make hex function work how can I achieve that the way you showed me is the way I could output(formatting) is that correct ? ....why it gives me negative numbers ?

+ You passed to the funtion call with mismatch
data type.
it is an integer Y, not a character Y.
Here is your call:
X = Convert(Y);
while you define the Convert funtion as:
int Convert(char val )

I think you should redefine as:

int Convert(int val)
{
}

+ Also, you might think of defining the formal parameter and actual parameter as UNSIGNED INT.

I think it should work!

DV007

/*=======================================*
* Say What You Mean. Mean What You Say. *
*=======================================*/

Originally posted by Abdi
Hi Hammer,

I want definitely to make hex function work how can I achieve that the way you showed me is the way I could output(formatting) is that correct ? ....why it gives me negative numbers ?

If you don't want to do it the easy way (like in my example), you can do it the hard way of reading input as a string, the checking each character in the string to ensure it'sa valid hex characters, then perform the appropriate maths to get the decimal version.

All in all, I think you should stick with scanf(), or maybe sscanf is you want to read input as a string. This then does all the hard work for you.