Thread: Extracting individual digits from a short

Hi,

I need to pass 2 shorts to a function and then extract each individal digit in the shorts to pass on to another function. E.g if i pass 90 as the value in the lower variable i first have to format it corretly (90 must be 0090 etc) and then pass each of digits to a new function to be displayed larger on screen etc. So

void displayNumber(short lower, short higher){
char lowerBuffer[50]={0};
char higherBuffer[50]={0};
char temp[10]={0};
short number;

/* using sprintf to format the number */
sprintf(lowerBuffer, "%04u", lower);
sprintf(higherBuffer, "%04u", higher);

/* get the digit i want and and the null term. */
temp[0] = lowerBuffer[0]; temp[1] = "\0";
number = atoi(temp)); /* convert it to number */
/* use function to display it on screen */
_OPTREX_number(number, 5, 10); /* ignore the two last par.*/

temp[0] = lowerBuffer[1]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 6, 10); /* ignore the two last par.*/

temp[0] = lowerBuffer[2]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 7, 10); /* ignore the two last par.*/

temp[0] = lowerBuffer[3]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 8, 10); /* ignore the two last par.*/

_OPTREX_number(10, 5, 10); /*10 is a colon */

temp[0] = higherBuffer[0]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 10, 10); /* ignore the two last par.*/

temp[0] = higherBuffer[1]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 11, 10); /* ignore the two last par.*/

temp[0] = higherBuffer[2]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 12, 10); /* ignore the two last par.*/

temp[0] = higherBuffer[3]; temp[1] = "\0";
number = atoi(temp));
_OPTREX_number(number, 13, 10); /* ignore the two last par.*/

}

So if i pass 900 and 300 on the display it would be: 0900:0300.

My question is:

Is there any quicker way in doing this. e.g. is the a way to convert use the lower and higher buffers more directly to convert it to a single digit. e.g _OPTREX_number(/*conversomehow)lowerBuffer[0], 5, 10)

G'n'R

Hi,

I have found a way. I can do this:

char lowerBuffer[50] is: 0900.

_OPTREX_number((short)(lowerBuffer[0]-48, 5, 8); or

in a printf function:

printf("%u", (unsigned short)lowerBuffer[0]-48); /* output 0 */

Since the dec value of lowerBuffer[0] will always be 48 greater than the dec value i want.

BUT, is this safe??

G'n'R

cool thanks. I will check out the loop thing.

G'n'R

If you want to seperate the digits from a number, padding it to 4 digits and don't want to have to convert to a character and back again then something like this will do the trick -

Code:

int main()
{

    short i,j,firstnumber = 44,secondnumber=36;
    short firstdigits [4]={0},seconddigits[4]={0};


    
    for (i=1000,j=0;i>0;i/=10,j++)
    {
        firstdigits[j] = firstnumber/i;
        firstnumber%=i;
    }
        
    
    for (i=1000,j=0;i>0;i/=10,j++)
    {
        seconddigits[j] = secondnumber/i;
        secondnumber%=i;
    }

        
    
return 0;
}

but if you want to maintain the original numbers you'll have to make a copy of them before the for loops.

Nice solution Zen. I have saved it. Thanks

G'n'R

Hi
another easy way of doing it

int main(int argc, char* argv[])
{
char str[5];
short arr[4];
num=30;
sprintf(str,"%04u",num); /* str -> 0030 */
sscanf(str,"%01d%01d%01d%01d",&arr[0], &arr[1], &arr[2], &arr[3]); /* arr -> {0,0,3,0} */
}

sorry missed out the "int"
Read as
int main(int argc, char* argv[])
{
char str[5];
short arr[4];
short num=30;

sprintf(str,"%04u",num); /* str -> 0030 */
sscanf(str,"%01d%01d%01d%01d",
&arr[0],&arr[1],&arr[2],&arr[3]); /* arr -> {0,0,3,0} */
}