String to integer to ascii

[Merrissey]

Lets say I have the following as a string:

097102099105110

What I want to do is find the ascii character represented by every set of 3 digits. So the ascii character of 97, then 102, 99, 105 and then 110.

Could anybody point me in the right direction here?

[Dave Sinkula]

One way:

#include <stdio.h>

int main(void)
{
   const char text[] = "097102099105110";
   int i, value[5];
   if ( sscanf(text, "%3d%3d%3d%3d%3d", &value[0],
			   &value[1], &value[2], &value[3], &value[4]) == 5 )
   {
	  for ( i = 0; i < 5; ++i )
	  {
		 printf("value[%d] = %d\n", i, value[i]);
	  }
   }
   return 0;
}

/* my output
value[0] = 97
value[1] = 102
value[2] = 99
value[3] = 105
value[4] = 110
*/

[Dave Sinkula]

Another way:

#include <stdio.h>

int main(void)
{
   const char text[] = "097102099105110", *ptr = text;
   int i, value;
   while ( sscanf(ptr, "%3d%n", &value, &i) == 1 )
   {
	  printf("value = %d\n", value);
	  ptr += i;
   }
   return 0;
}

/* my output
value = 97
value = 102
value = 99
value = 105
value = 110
*/

[Dave Sinkula]

Sorry for multiple posts -- I just now noticed the ASCII part.

Assuming your system is ASCII, it's quite easy to convert the integer value to ASCII (do nothing).

#include <stdio.h>
 
int main(void)
{
   const char text[] = "097102099105110", *ptr = text;
   int i, value;
   while ( sscanf(ptr, "%3d%n", &value, &i) == 1 )
   {
   printf("value = %3d = '%c'\n", value, value);
   ptr += i;
   }
   return 0;
}
 
/* my output
value =  97 = 'a'
value = 102 = 'f'
value =  99 = 'c'
value = 105 = 'i'
value = 110 = 'n'
*/

[tlee]

Hi Dave,
What is the %n used for in sscanf(ptr, "%3d%n", &value, &i)? Thanks.

[Dave Sinkula]

>What is the %n used for in sscanf(ptr, "%3d%n", &value, &i)?

No input is consumed. The corresponding argument shall be a pointer to signed integer into which is to be written the number of characters read from the input stream so far by this call to the fscanf function. Execution of a %n directive does not increment the assignment count returned at the completion of execution of the fscanf function. No argument is converted, but one is consumed. If the conversion specification includes an assignment suppressing character or a field width, the behavior is undefined.

[FireNet]

char chr = 'a';

cout<<chr; //will show the char
cout<<(int)chr; //will show the ancii code

chr = 232;

cout<<chr; //will show what ever 232 repesents
cout<<(int)chr; //will show the ancii code i.e 232

[Msnart]

char chr = 'a';

cout<<chr; //will show the char
cout<<(int)chr; //will show the ancii code

chr = 232;

cout<<chr; //will show what ever 232 repesents
cout<<(int)chr; //will show the ancii code i.e 232

So if i had a character array (string):

tempChar[10] = '44\0abcdefg';

How do I convert that string into the integer 44? I've tried:

anInt = (int)tempChar;

hoping that it would take the string up to the null character \0 and turn it into an int, but no dice. Any suggestions?

[Dave Sinkula]

Don't cast, use atoi.