document string_fibonacci

others/string_fibonacci.cpp

@@ -1,82 +1,88 @@
-//This Programme returns the Nth fibonacci as a string.
-//The method used is manual addition with carry and placing it in a string which is called string addition
-//This makes it have no bounds or limits
+/**
+ * @file
+ * @brief This Programme returns the Nth fibonacci as a string.
+ *
+ * The method used is manual addition with carry and placing it in a string
+ * which is called string addition This makes it have no bounds or limits
+ *
+ * @see fibonacci_large.cpp, fibonacci_fast.cpp, fibonacci.cpp
+ */
 
 #include <iostream>
-#include <string>
+#ifdef _MSC_VER
+#include <string>  // use this for MS Visual C
+#else
+#include <cstring>  // otherwise
+#endif
 
-using namespace std;
-
-string add(string a, string b)
-{
-    string temp = "";
+/**
+ * function to add two string numbers
+ * \param [in] a first number in string to add
+ * \param [in] b second number in string to add
+ * \returns sum as a std::string
+ */
+std::string add(std::string a, std::string b) {
+    std::string temp = "";
 
     // carry flag
     int carry = 0;
 
     // fills up with zeros
-    while ((int)a.length() < (int)b.length())
-    {
+    while ((int)a.length() < (int)b.length()) {
         a = "0" + a;
     }
 
     // fills up with zeros
-    while ((int)b.length() < (int)a.length())
-    {
+    while ((int)b.length() < (int)a.length()) {
         b = "0" + b;
     }
 
     // adds the numbers a and b
-    for (int i = a.length() - 1; i >= 0; i--)
-    {
+    for (int i = a.length() - 1; i >= 0; i--) {
         char val = (char)(((a[i] - 48) + (b[i] - 48)) + 48 + carry);
-        if (val > 57)
-        {
+        if (val > 57) {
             carry = 1;
             val -= 10;
-        }
-        else
-        {
+        } else {
             carry = 0;
         }
         temp = val + temp;
     }
 
     // processes the carry flag
-    if (carry == 1)
-    {
+    if (carry == 1) {
         temp = "1" + temp;
     }
 
     // removes leading zeros.
-    while (temp[0] == '0' && temp.length() > 1)
-    {
+    while (temp[0] == '0' && temp.length() > 1) {
         temp = temp.substr(1);
     }
 
     return temp;
 }
 
-void fib_Accurate(long long n)
-{
-    string tmp = "";
-    string fibMinus1 = "1";
-    string fibMinus2 = "0";
-    for (long long i = 0; i < n; i++)
-    {
+/** Fibonacci iterator
+ * \param [in] n n^th Fibonacci number
+ */
+void fib_Accurate(long long n) {
+    std::string tmp = "";
+    std::string fibMinus1 = "1";
+    std::string fibMinus2 = "0";
+    for (long long i = 0; i < n; i++) {
         tmp = add(fibMinus1, fibMinus2);
         fibMinus2 = fibMinus1;
         fibMinus1 = tmp;
     }
-    cout << fibMinus2;
+    std::cout << fibMinus2;
 }
 
-int main()
-{
+/** main function */
+int main() {
     int n;
-    cout << "Enter whatever number N you want to find the fibonacci of\n";
-    cin >> n;
-    cout << n << " th Fibonacci is \n";
+    std::cout << "Enter whatever number N you want to find the fibonacci of\n";
+    std::cin >> n;
+    std::cout << n << " th Fibonacci is \n";
     fib_Accurate(n);
 
     return 0;