The C Programming Language (K&R) 01x11—Func for Temp Convert—Exercise 1-15

Exercise 1-15 from “The C Programming Language” by Brian Kernighan and Dennis Ritchie aka K&R.

Rewrite the temperature conversion program of Section 1.2 to use a function for conversion.

The first code for section 1.2 is here.

Adding a function to do the conversion calculation is straightforward. I added an argument to choose between converting from C to F or F to C.

Sample Code.

I am using Visual C++ 2010 and created the sample code as a console application.

// Function prototype.

float TempConv(int temp, bool direction);

// The standard library includes the system function.

#include <cstdlib>

// Standard I/O library.

#include <cstdio>

// Constants.

#define LOWER 0 /* lower limit of table */

#define UPPER 300 /* upper limit */

#define STEP 20 /* step size */

int main()

{

     int temp;

    

     // Create table of F to C.

     printf("  F\t    C\n");

     for (temp = LOWER; temp <= UPPER; temp = temp + STEP)

           printf("%3d\t%6.1f\n", temp, TempConv(temp, true));

     // Create table of C to F.

     printf("\n\n  C\t    F\n");

     for (temp = -20; temp <= 50; temp = temp + 5)

           printf("%3d\t%6.1f\n", temp, TempConv(temp, false));

     // Keep console window open.

     system("pause");

     // Return some value.

     return 0;

} // end main

 

float TempConv(int temp, bool direction)

{

     if (direction)

           // Convert Farhenheit to Celcius/

           return (5.0/9.0)*(temp-32.0);

     else

           // Convert Celcius to Farhenheit.

           return temp * (9.0/5.0) + 32.0;

}

Output.