Using a single byte character in calculation.. 2

[johnfdutcher]

I have an input file to process written in another language.

One or more fields of (1) byte in length contain digits to be treated as integers.

Simply multiplying the variable name for the field by a constant gives erroneous mathmatical results:

char day_of_week = 7;
int meal_index = 0;

meal_index = 3 * day_of_week;
OR
meal_index = 3 * (int)day_of_week;

Both of the above give 156, where what is desired is 21 ???

 

[Clairvoyant1332]

It sounds like the variable

day_of_week

contains the ASCII value for the character '7', which is 52, instead of the number 7. Try doing this:

meal_index = 3 * (day_of_week - '0');

This will convert the ASCII character '7' to the number 7.

Dennis

 

[cptk]

Sounds like you want to take a character constant
and do some calculation.

Try this example setup ...

char cc = '7';
int iv;

sscanf(&cc,"%i",&iv);
printf("Result of mult. a char const: %i\n", iv*iv);

This will produce value 49