Program line |
Description |
Block algorithm |

1 | Every program in the pascal must start with the keyword program preceding the name of the program, it adds nothing to the implementation of the algorithm. | - |

3 - 15 | We declare and define a linear procedure that implements the algorithm of solving a linear equation. | 4 |

17 | We declare all variables used in the main program. In a pascal, we must do this before the keyword begin, which starts the operating part of the code. | - |

18 | The beginning of the program code. | 1 |

19 - 24 | On the screen, we print the prompts for the user and load the values of the coefficients a, b and c entered into the corresponding, previously declared, variables. | 2 |

25 | We check if the coefficient a is equal to 0. If this is the case with the linear equation. | 3 |

26 | In this line we will only find ourselves if a = 0, ie when the equation is a linear equation. We invoke procedure linear(b, c) that realizes the algorithm of solving a linear equation. It is worth noting that the coefficient at the first power of the variable x is marked with the symbol b, and the free expression c (traditionally in the linear equation, a and b are used respectively). | 4 |

27 | else, i.e. otherwise. At this point, the solution of the equation begins, when a ≠ 0, in other words when we actually deal with a quadratic equation. | - |

28 | We calculate the value of the delta variable. | 5 |

29 | We check if delta < 0. | 6 |

30 | When delta < 0, we print an appropriate message about the lack of solutions. | 7 |

31 | Here the program block begins when the delta is not less than zero, ie when the equation has solutions (one or two). | - |

32 | We check if delta = 0. | 8 |

33 | We calculate and store in the x variable the solution of the equation (single, double - delta=0). | 9 |

34 | We display the calculated result. | 10 |

35 | We start the program block executed in the situation when the condition delta = 0 (and earlier delta <0 and a ≠ 0) was not met. | - |

36 - 37 | We calculate solutions and their values we assign to variables x1 and x2. | 11 |

38 - 39 | We display the calculated result - two solutions of the quadratic equation. | 12 |

40 - 41 | We close the blocks of compound instructions. | - |

42 | The end of the program implementation. | 13 |