Using the previous program as a reference, we can define the variables lower, upper, and step to represent the lower bounds, upper bounds, and the step size, as well as celsius and fahr to store the temperatures.
#include <stdio.h>
main()
{
float fahr, celsius;
int lower, upper, step;
lower = 0; /* lower limit of temperature table */
upper = 300; /* upper limit */
step = 20; /* step size */
}
Because we want to print a table that converts Celsius temperatures
into Fahrenheit, we initialize celsius to
lower and set the condition of our while-loop
to celsius <= upper, whilst incrementing
celsius by step at the end of each iteration.
This way, the value of celsius starts at
lower and increments by step repeatedly until it
reaches upper.
#include <stdio.h>
main()
{
float fahr, celsius;
int lower, upper, step;
lower = 0; /* lower limit of temperature table */
upper = 300; /* upper limit */
step = 20; /* step size */
celsius = lower;
while (celsius <= upper)
celsius = celsius + step;
}
The Fahrenheit-Celsius program subtracted 32 from fahr and
multiplied the result by 5/9 to get the corresponding Celsius
temperature, so in order to convert celsius to
fahr, we have to multiply celsius by 9/5 and then
add 32. This can be written as the expression
(9.0/5.0) * celsius + 32.0. Once we assign the converted
temperature to fahr, we can print the Celsius column on the
left and the Fahrenheit column on the right to better reflect the fact
that we are converting from Celsius to Fahrenheit.
#include <stdio.h>
main()
{
float fahr, celsius;
int lower, upper, step;
lower = 0; /* lower limit of temperature table */
upper = 300; /* upper limit */
step = 20; /* step size */
printf("Celsius Fahr\n");
celsius = lower;
while (celsius <= upper) {
fahr = (9.0/5.0) * celsius + 32.0;
printf("%7.0f %4.0f\n", celsius, fahr);
celsius = celsius + step;
}
}Note: we do not need to print the decimal places of fahr since a multiple of twenty—our step size—times 9/5 will always be an integer.