Solved strong numbers in range

Author: Ankononenko

For loop/48. Strong numbers in range.c

@@ -0,0 +1,120 @@
+// Copyright 2022 finchren
+/*
+Write a C program to find Strong Numbers within a range of numbers
+Test Data :
+Input starting range of number : 1
+Input ending range of number: 200
+Expected Output :
+The Strong numbers are :
+1 2 145
+
+Rework regular Sstrong number solution to work in a range:
+ + 1. Correct the input
+ + 2. Find numbers inside a range
+ + 3. Test:
+    Input: 1 and 1000000. Output:
+    1 2 145 40585
+ + 4. Cpplint
+ + 5. Add and push
+*/
+
+#include <stdio.h>
+
+int input_start();
+int input_end();
+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_strong(int start, int end);
+
+int main() {
+    int start = input_start();
+    if (start >= 0) {
+        int end = input_end();
+        if (end >= 0) {
+            print_is_strong(start, end);
+        } else {
+        print_invalid_input();
+        }
+    } else {
+        print_invalid_input();
+    }
+    return 0;
+}
+
+void print_is_strong(int start, int end) {
+    printf("The Strong numbers are:\n");
+    for (int i = start; i <= end; i++) {
+        if (is_strong(i)) {
+            printf("%d ", i);
+        }
+    }
+}
+
+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_end() {
+    int end;
+    char endline;
+    printf("Input starting range of number:\n");
+    if (!scanf("%d%c", &end, &endline) || endline != '\n') {
+        end = -1;
+    }
+    return end;
+}
+
+int input_start() {
+    int start;
+    char endline;
+    printf("Input ending range of number:\n");
+    if (!scanf("%d%c", &start, &endline) || endline != '\n') {
+        start = -1;
+    }
+    return start;
+}