| 1 | #include <stdio.h> |
| 2 | #include <stdbool.h> |
| 3 | #include <stdlib.h> |
| 4 | |
| 5 | /** Pointer to a function with this profile */ |
| 6 | typedef int(*operation_cb)(int v1, int v2); |
| 7 | |
| 8 | /** Describe a single operation */ |
| 9 | typedef struct { |
| 10 | const char* label; |
| 11 | operation_cb cb; |
| 12 | } operation_t; |
| 13 | |
| 14 | int doAddition(int v1, int v2); |
| 15 | int doSubstraction(int v1, int v2); |
| 16 | int doMultiplication(int v1, int v2); |
| 17 | int doXOR(int v1, int v2); |
| 18 | |
| 19 | /** All available operations */ |
| 20 | operation_t operations[4] = { |
| 21 | { |
| 22 | "Addition", |
| 23 | doAddition |
| 24 | }, |
| 25 | { |
| 26 | "Substraction", |
| 27 | doSubstraction |
| 28 | }, |
| 29 | { |
| 30 | "Multiplication", |
| 31 | doMultiplication |
| 32 | }, |
| 33 | { |
| 34 | "XOR", |
| 35 | doXOR |
| 36 | } |
| 37 | }; |
| 38 | #define operations_count ((int) (sizeof(operations) / sizeof(operations[0]))) |
| 39 | |
| 40 | /** Display a prompt to the user then wait for an integer input. */ |
| 41 | void promptValue(const char* prompt, int* value) { |
| 42 | printf("%s:\n", prompt); |
| 43 | scanf("%d", value); |
| 44 | } |
| 45 | |
| 46 | void displayMenuEntry(int index, const char* label) { |
| 47 | printf("%d | %s\n", index, label); |
| 48 | } |
| 49 | |
| 50 | /** Display all available operations and an EXIT option. */ |
| 51 | void displayMenu() { |
| 52 | for (int menuIndex = 0; menuIndex < operations_count; ++menuIndex) { |
| 53 | displayMenuEntry(menuIndex + 1, operations[menuIndex].label); |
| 54 | } |
| 55 | |
| 56 | displayMenuEntry(operations_count + 1, "Exit"); |
| 57 | } |
| 58 | |
| 59 | /** Prompt the user for his operation choice. |
| 60 | * |
| 61 | * @return The selected operation. If the exit option is chosen, return NULL |
| 62 | */ |
| 63 | operation_t* promptOperation() { |
| 64 | displayMenu(); |
| 65 | |
| 66 | do { |
| 67 | int result; |
| 68 | promptValue("Choose an option", &result); |
| 69 | |
| 70 | if (result == (operations_count + 1)) { |
| 71 | return NULL; |
| 72 | } |
| 73 | |
| 74 | if (result >= 1 && result <= operations_count) { |
| 75 | return &operations[result - 1]; |
| 76 | } |
| 77 | |
| 78 | printf("Please choose a valid option (1-%d)\n", operations_count); |
| 79 | } while (true); |
| 80 | } |
| 81 | |
| 82 | int doAddition(int v1, int v2) { |
| 83 | return v1 + v2; |
| 84 | } |
| 85 | |
| 86 | int doSubstraction(int v1, int v2) { |
| 87 | return v1 - v2; |
| 88 | } |
| 89 | |
| 90 | int doMultiplication(int v1, int v2) { |
| 91 | return v1 * v2; |
| 92 | } |
| 93 | |
| 94 | int doXOR(int v1, int v2) { |
| 95 | return v1 ^ v2; |
| 96 | } |
| 97 | |
| 98 | int main() { |
| 99 | operation_t* operation = promptOperation(); |
| 100 | |
| 101 | if (operation == NULL) { |
| 102 | return 0; |
| 103 | } |
| 104 | |
| 105 | int initialValue; |
| 106 | promptValue("Initial value", &initialValue); |
| 107 | |
| 108 | do { |
| 109 | int nextValue; |
| 110 | promptValue("Next value", &nextValue); |
| 111 | |
| 112 | if (nextValue == 0) { |
| 113 | break; |
| 114 | } |
| 115 | |
| 116 | initialValue = operation->cb(initialValue, nextValue); |
| 117 | printf("Result: %d\n", initialValue); |
| 118 | } while (true); |
| 119 | } |