Solved strong number

Author: Ankononenko

For loop/47. Strong number.c

@@ -0,0 +1,133 @@
+// Copyright 2022 finchren
+/*
+Write a C program to check whether a number is a Strong Number or not
+Test Data :
+Input a number to check whether it is a Strong number: 15
+Expected Output :
+15 is not a Strong number.
+
++ 1. Take input
++ 2. Invalid input
++ 3.0 Figure out what is a Strong number: 
+    145 = 1! + 4! + 5!
++ 3.1 Write a factorial function
++ 3.2 Number of digits function
++ 3.3 Write power function
++ 3.3 Write function to check if Strong or not
++ 4. Output
++ 5. Test
++ 6. Cpplint test
++ 7. Add and push
+*/
+
+#include <stdio.h>
+
+int input_number();
+void print_invalid_input();
+int find_number_of_digits(int number);
+int find_factorial(int number);
+int power(int base, int exponent);
+int is_strong(int number);
+void print_is_armstrong(int number, int is_strong);
+void test(int number, int expected, int test_number);
+
+int main() {
+    // Regular run of the program
+    int number = input_number();
+    if (number >= 0) {
+        int is_strong_num = is_strong(number);
+        print_is_armstrong(number, is_strong_num);
+    } else {
+        print_invalid_input();
+    }
+    // Test runs
+    // First test, normal values
+    test(145, 1, 1);
+    // Normal value, false result
+    test(15, 0, 2);
+    // Min value
+    test(0, 1, 3);
+    // One
+    test(1, 1, 4);
+    // Big number
+    test(40585, 1, 5);
+    // Max value, false result
+    test(2147483647, 0, 6);
+    return 0;
+}
+
+// 0 - false, 1 - true
+void test(int number, int expected, int test_number) {
+    int actual = is_strong(number);
+    if (actual == expected) {
+        printf("Test #%d: number = %d, expected = %d, actual = %d\nSuccess\n",
+        test_number, number, expected, actual);
+    } else {
+        printf("Test #%d: number = %d, expected = %d, actual = %d\nFailed\n",
+        test_number, number, expected, actual);
+    }
+}
+
+void print_is_armstrong(int number, int is_strong) {
+    if (is_strong) {
+        printf("%d is a Strong number.\n", number);
+    } else {
+        printf("%d is not a Strong number.\n", number);
+    }
+}
+
+int is_strong(int number) {
+    int is_strong = 0, result = 0, temp_number = number,
+    one_digit, number_of_digits = find_number_of_digits(number);
+    for (int i = number_of_digits; i > 0; --i) {
+        one_digit = temp_number / (1 * power(10, i - 1));
+        temp_number -= one_digit * (1 * power(10, i - 1));
+        result += find_factorial(one_digit);
+    }
+    if (number == result) {
+        is_strong = 1;
+    }
+    return is_strong;
+}
+
+int find_factorial(int number) {
+    int result = 1;
+    for (int i = 1; i <= number; i++) {
+        result *= i;
+    }
+    return result;
+}
+
+int find_number_of_digits(int number) {
+    int result = 0;
+    for (int i = number; i > 0; i /= 10) {
+        ++result;
+    }
+    return result;
+}
+
+int power(int base, int exponent) {
+    int result = base;
+    if (exponent != 0) {
+        for (int i = 2; i <= exponent; i++) {
+            result *= base;
+        }
+    } else {
+        result = 1;
+    }
+    return result;
+}
+
+void print_invalid_input() {
+    printf("n/a");
+}
+
+int input_number() {
+    int number;
+    char endline;
+    printf("Input a number to check whether it is a Strong number:\n");
+    if (!scanf("%d%c", &number, &endline) || endline != '\n') {
+        number = -1;
+    }
+    return number;
+}