sorcerer_see

PS I synthesize here in my own words what K&R teach, re-write all their example programs, character by character, solve all the C exercises they hand out. I comment to what K&R teach cursively. I do not copy-paste anything from the book! In regards to the percentages listed: books often have prefaces with Roman numbers and often also lengthy Appendices. In my calculation I include all pages that I effectively study and synthesize.

TCPL 2Ed - Page 012 to 013 - 6.41% Completion

k-r_prg003.c

k-r_prg003.out

There are only a few differences between the former version of the Fahrenheit to Celsius conversion program and this one:

fahr and celsius are decared as float instead of integer

float allows for fractional numbers, so that they are not truncated and therefor more accurate

the printout looks better because the numbers are equally aligned from the right

printf("%3.0f %6.1f\n", fahr, celsius);

%3.0f
says a floating-point number is to be printed at least 3 characters wide, without decimal point and no fraction digits,

%6.1f
says to print a number presenting Celsius that will be at least 6 characters wide, and having 1 digit after the comma

%.2f
says that width is not constrained (no character count given) and to print 2 characters after the decimal point. (%)f is saying to print the number as floating-point.

A few more examples:

%d = print as decimal integer
%6d = print as decimal integer, at least 6 characters wide
%f = print as floating-point
%6f = print as a floating point, at least 6 characters wide
%.2f = print as floating-point, with 2 characters after the decimal point
%6.2f = print as floating-point, at least 6 wide and with 2 characters after the decimal point

printf recognizes, among others, %o for octal, %x for hexadecimal, %c for character, %s for character string and %% for % itself.

the formula is written in a more natural manner

it became possible to just write (5/9) and not needed to use a roundabout to avoid all zero's: 5 * (fahr -
) / 9;

C mechanics:

If an arithmetic operator has integer operands an integer operation is performed
If an arithmetic operator has one floating-point operand and one integer operand, the integer will be converted to floating-point before the operation is performed.
Had we written fahr-32, it would have been converted to 32.0. Even though 32.0 = 32 and thus is an integer, writing it like 32.0 makes it clear to human-readers that it is treated by the program as having a floating-point nature. So that readers know that decimal fractions are taken in account.

The C rules for the conversion of integers to floating-point is being spoken of in detail in Chapter 2.

As of now it is worth-while to notice that the int in

fahr = lower;

and

while (fahr <= upper)

also gets converted to float before the operation is done.

Exercise 1-3
Modify the temperature conversion program to print a heading above the table.

k-r_exc1-3.c

k-r_exc1-3.out

Exercise 1-4
Write a program to print the corresponding Celsius to Fahrenheit table.

At first I added decimal digits to the Fahrenheit output but since none of the Celsius numbers listed has, when converted, a fractional Fahrenheit number as outcome, I omitted decimals, to make the program look better.

k-r_exc1-4.c