The C Programming Language, 2nd Edition, by Kernighan and Ritchie
Exercise 1.04 on page 13

Write a program to print the corresponding Celsius to Fahrenheit table.

Solution by Richard Heathfield

#include <stdio.h>

int main(void)
{
  float fahr, celsius;
  int lower, upper, step;

  lower = 0;
  upper = 300;
  step = 20;

  printf("C     F\n\n");
  celsius = lower;
  while(celsius <= upper)
  {
    fahr = (9.0/5.0) * celsius + 32.0;
    printf("%3.0f %6.1f\n", celsius, fahr);
    celsius = celsius + step;
  }
  return 0;
}