program ex11;
var a, tconverted: real;
f, scale: char;
begin
writeln ('Enter a number for temperature conversion ');
readln (a);
writeln ('Enter c to convert from C to F or f to convert from F to C');
readln (f);
if f in ['c', 'C'] then
begin
tconverted := a * 9 / 5 +
32;
scale:='F';
end
else
if f in ['f', 'F'] then
begin
tconverted:= (a - 32) * 5 / 9;
scale:='C';
end;
writeln ('Converted temperature is: ', tconverted: 8:2, ' degrees ',
scale);
readln;
end.
We get a single number from the user. This is a temperature in either degrees C or F. We ask the user to enter the type of temperature on the input number, 'c' or 'f'. In case the user enters 'C' or 'F' we use the in ['c', 'C'] construction (we could use f='c' or f='f'). If the user enters 'f' then the output scale is C, if 'c' then 'F'. We use the scale variable to output the correct letter in the output statement.
Note the absence of a ';' after the end before the else - if..then..else is continuous so should have no semi-colon before else.