[C++] Add solution for Calories From Fat

Solutions/Calories From Fat/calories.cpp

@@ -0,0 +1,67 @@
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <cmath>
+#include <numeric>
+
+using namespace std;
+
+vector<float> calculate_calories(const string& line, const int* calories_per_gram) {
+    istringstream sin(line);
+    string types[5];
+    sin >> types[0] >> types[1] >> types[2] >> types[3] >> types[4];
+
+    vector<int> missed_indices;
+    float numbers[5] = {0, 0, 0, 0, 0};
+    float percent_total = 0;
+    float temp_total = 0;
+    vector<float> total_calories(5, 0);
+
+    for (int i = 0; i < 5; ++i) {
+        char type = types[i].back();
+        float number = stof(types[i].substr(0, types[i].length() - 1));
+        numbers[i] = number;
+
+        if (type == '%') {
+            percent_total += number;
+            missed_indices.push_back(i);
+        } else if (type == 'g') {
+            total_calories[i] = calories_per_gram[i] * number;
+            temp_total += calories_per_gram[i] * number;
+        } else {
+            total_calories[i] = number;
+            temp_total += number;
+        }
+    }
+
+    temp_total /= (1 - percent_total / 100.0);
+    for (int index : missed_indices) {
+        float number = numbers[index];
+        total_calories[index] = temp_total * (number / 100.0);
+    }
+
+    return total_calories;
+}
+
+int main() {
+    int calories_per_gram[5] = {9, 4, 4, 4, 7};
+    string line;
+
+    while (true) {
+        getline(cin, line);
+        if (line == "-") break;
+        vector<float> total_calories = calculate_calories(line, calories_per_gram);
+        while (true) {
+            getline(cin, line);
+            if (line == "-") break;
+            vector<float> current_calories = calculate_calories(line, calories_per_gram);
+            for (int i = 0; i < 5; ++i) {
+                total_calories[i] += current_calories[i];
+            }
+        }
+        cout << round(100 * total_calories[0] / accumulate(total_calories.begin(), total_calories.end(), 0.0f)) << "%" << endl;
+    }
+
+    return 0;
+}