Merge branch 'cmake'

* cmake:
  MSVC does not know cstring-use string-for toString
  for windows build, MSVC knows C++-14 and not 11
  remove redundant /Za for VC
  add cstring for std::to_string()
  updating DIRECTORY.md
  fixed dynamic array
  removed in-favor of chronos library of c++11
  updating DIRECTORY.md
  fixed windows build error
  fixed lint
  file rename
  cin accepts only one variable at a time & fixed cpplint
  improved documentation
  `rand_r` is non-portable and obsolete
  newline character at EOF of gitignore

CMakeLists.txt

@@ -8,6 +8,14 @@ project(Algorithms_in_C++
 # set(CMAKE_CXX_CPPLINT "~/anaconda3/bin/cpplint --filter=-legal/copyright --std=c++11")
 # find_program(CLANG_FORMAT "clang-format")
 
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+if(MSVC)
+    set(CMAKE_CXX_STANDARD 14)
+    add_compile_definitions(_CRT_SECURE_NO_WARNINGS)
+endif(MSVC)
+
 option(USE_OPENMP "flag to use OpenMP for multithreading" ON)
 
 cmake_policy(SET CMP0054 NEW)
@@ -40,21 +48,13 @@ if(DOXYGEN_FOUND)
     )
 endif()
 
-set(CMAKE_CXX_STANDARD 11)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-
-if(MSVC)
-    add_compile_definitions(_CRT_SECURE_NO_WARNINGS)
-    add_compile_options(/Za)
-endif(MSVC)
-
 add_subdirectory(math)
 add_subdirectory(others)
 add_subdirectory(computer_oriented_statistical_methods)
 
 if(USE_OPENMP)
     find_package(OpenMP)
-    if (OpenMP_C_FOUND)
+    if (OpenMP_CXX_FOUND)
         message(STATUS "Building with OpenMP Multithreading.")
     else()
         message(STATUS "No OpenMP found, no multithreading.")

DIRECTORY.md

@@ -141,8 +141,7 @@
   * [Gcd Of N Numbers](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/gcd_of_n_numbers.cpp)
   * [Happy Number](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/happy_number.cpp)
   * [Matrix Exponentiation](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/matrix_exponentiation.cpp)
-  * [Measure Time Elapsed](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/measure_time_elapsed.cpp)
-  * [Palindromeofnumber](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/Palindromeofnumber.cpp)
+  * [Palindrome Of Number](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/palindrome_of_number.cpp)
   * [Paranthesis Matching](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/paranthesis_matching.cpp)
   * [Pascal Triangle](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/pascal_triangle.cpp)
   * [Primality Test](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/others/primality_test.cpp)

computer_oriented_statistical_methods/gaussian_elimination.cpp

@@ -6,7 +6,11 @@ int main() {
     std::cout << "Matrix size: ";
     std::cin >> mat_size;
 
-    double mat[mat_size + 1][mat_size + 1], x[mat_size][mat_size + 1];
+    double **mat = new double *[mat_size + 1], **x = new double *[mat_size];
+    for (i = 0; i <= mat_size; i++) {
+        mat[i] = new double[mat_size + 1];
+        if (i < mat_size) x[i] = new double[mat_size + 1];
+    }
 
     std::cout << std::endl << "Enter value of the matrix: " << std::endl;
     for (i = 0; i < mat_size; i++) {
@@ -49,5 +53,13 @@ int main() {
 
         std::cout << "x" << i << "= " << x[i][i] << std::endl;
     }
+
+    for (i = 0; i <= mat_size; i++) {
+        delete[] mat[i];
+        if (i < mat_size) delete[] x[i];
+    }
+    delete[] mat;
+    delete[] x;
+
     return 0;
 }

math/fast_power.cpp

@@ -1,22 +1,29 @@
-#include <iostream>
-#include <cstdlib>
-#include <cstdint>
-#include <cassert>
-#include <ctime>
-#include <cmath>
-
-/*
-    Program that computes a^b in O(logN) time.
+/**
+ * @file
+    Program that computes \f$a^b\f$ in \f$O(logN)\f$ time.
     It is based on formula that:
-        case1) if b is even: a^b = a^(b/2) * a^(b/2) = (a^(b/2))ˆ2
-        case2) if b is odd: a^b = a^((b-1)/2) * a^((b-1)/2) * a = (a^((b-1)/2))^2 * a
-    We can compute a^b recursively using above algorithm.
+    1. if \f$b\f$ is even: \f$a^b = a^\frac{b}{2} \cdot a^\frac{b}{2} =
+ {a^\frac{b}{2}}^2\f$
+    2. if \f$b\f$ is odd: \f$a^b = a^\frac{b-1}{2} \cdot
+ a^\frac{b-1}{2} \cdot a = {a^\frac{b-1}{2}}^2 \cdot a\f$
+
+ We can compute \f$a^b\f$
+ recursively using above algorithm.
 */
 
+#include <cassert>
+#include <cmath>
+#include <cstdint>
+#include <cstdlib>
+#include <ctime>
+#include <iostream>
+
+/**
+ * algorithm implementation for \f$a^b\f$
+ */
 double fast_power_recursive(int64_t a, int64_t b) {
     // negative power. a^b = 1 / (a^-b)
-    if (b < 0)
-        return 1.0 / fast_power_recursive(a, -b);
+    if (b < 0) return 1.0 / fast_power_recursive(a, -b);
 
     if (b == 0) return 1;
     int64_t bottom = fast_power_recursive(a, b >> 1);
@@ -31,14 +38,13 @@ double fast_power_recursive(int64_t a, int64_t b) {
     return result;
 }
 
-/*
+/**
     Same algorithm with little different formula.
     It still calculates in O(logN)
 */
 double fast_power_linear(int64_t a, int64_t b) {
     // negative power. a^b = 1 / (a^-b)
-    if (b < 0)
-        return 1.0 / fast_power_linear(a, -b);
+    if (b < 0) return 1.0 / fast_power_linear(a, -b);
 
     double result = 1;
     while (b) {
@@ -50,30 +56,28 @@ double fast_power_linear(int64_t a, int64_t b) {
 }
 
 int main() {
-    std::srand(time(NULL));
+    std::srand(std::time(nullptr));
     std::ios_base::sync_with_stdio(false);
 
     std::cout << "Testing..." << std::endl;
     for (int i = 0; i < 20; i++) {
-        unsigned int *rand1, *rand2;
-        int a = rand_r(rand1) % 20 - 10;
-        int b = rand_r(rand2) % 20 - 10;
+        int a = std::rand() % 20 - 10;
+        int b = std::rand() % 20 - 10;
         std::cout << std::endl << "Calculating " << a << "^" << b << std::endl;
         assert(fast_power_recursive(a, b) == std::pow(a, b));
         assert(fast_power_linear(a, b) == std::pow(a, b));
 
-        std::cout << "------ " << a << "^" << b << " = "<<
-            fast_power_recursive(a, b) << std::endl;
+        std::cout << "------ " << a << "^" << b << " = "
+                  << fast_power_recursive(a, b) << std::endl;
     }
 
     int64_t a, b;
     std::cin >> a >> b;
 
-    std::cout << a << "^" << b << " = "<<
-        fast_power_recursive(a, b) << std::endl;
+    std::cout << a << "^" << b << " = " << fast_power_recursive(a, b)
+              << std::endl;
 
-    std::cout << a << "^" << b << " = "<<
-        fast_power_linear(a, b) << std::endl;
+    std::cout << a << "^" << b << " = " << fast_power_linear(a, b) << std::endl;
 
     return 0;
 }

others/Palindromeofnumber.cpp

@@ -1,23 +0,0 @@
-#include <iostream>
-#include <algorithm>
-
-using namespace std;
-
-int main()
-{
-	int num;
-	cout << "Enter number = ";
-	cin >> num;
-
-	string s1 = to_string(num);
-	string s2 = s1;
-
-	reverse(s1.begin(), s1.end());
-
-	if (s1 == s2)
-		cout << "true";
-	else
-		cout << "false";
-
-	return 0;
-}

others/measure_time_elapsed.cpp

@@ -1,19 +0,0 @@
-// To calculate the time taken by a code to execute
-#include <sys/time.h>
-#include <iostream>
-
-__int64_t getTimeInMicroseconds() {
-    struct timeval start;
-    gettimeofday(&start, NULL);
-    return start.tv_sec * 1000000 + start.tv_usec;
-}
-
-// write function sample(args)
-
-int main() {
-    // write code
-    __int64_t starttime = getTimeInMicroseconds();
-    // sample(args) function run
-    // Any other functions (if present) run
-    std::cout << getTimeInMicroseconds() - starttime;
-}

others/palindrome_of_number.cpp

@@ -0,0 +1,27 @@
+#include <algorithm>
+#include <iostream>
+
+#ifdef _MSC_VER
+// Required to compile std::toString function using MSVC
+#include <string>
+#else
+#include <cstring>
+#endif
+
+int main() {
+    int num;
+    std::cout << "Enter number = ";
+    std::cin >> num;
+
+    std::string s1 = std::to_string(num);
+    std::string s2 = s1;
+
+    reverse(s1.begin(), s1.end());
+
+    if (s1 == s2)
+        std::cout << "true";
+    else
+        std::cout << "false";
+
+    return 0;
+}

others/sparse_matrix.cpp

@@ -1,41 +1,46 @@
-/*A sparse matrix is a matrix which has number of zeroes greater than (m*n)/2,
-where m and n are the dimensions of the matrix.*/
-#include <iostream>
-using namespace std;
+/** @file
+ * A sparse matrix is a matrix which has number of zeroes greater than
+ * \f$\frac{m*n}{2}\f$, where m and n are the dimensions of the matrix.
+ */
 
-int main()
-{
+#include <iostream>
+
+int main() {
     int m, n;
     int counterZeros = 0;
-  cout << "Enter dimensions of matrix (seperated with space): ";
-  cin >> m >> n;
-  int a[m][n];
-  cout << "Enter matrix elements:";
-  cout << "\n";
+
+    std::cout << "Enter dimensions of matrix (seperated with space): ";
+    std::cin >> m;
+    std::cin >> n;
+
+    int **a = new int *[m];
+    for (int i = 0; i < m; i++) a[i] = new int[n];
+
+    std::cout << "Enter matrix elements:";
+    std::cout << "\n";
 
     // reads the matrix from stdin
-  for (int i = 0; i < m; i++)
-  {
-    for (int j = 0; j < n; j++)
-    {
-      cout << "element? ";
-      cin >> a[i][j];
+    for (int i = 0; i < m; i++) {
+        for (int j = 0; j < n; j++) {
+            std::cout << "element? ";
+            std::cin >> a[i][j];
         }
     }
 
     // counts the zero's
-  for (int i = 0; i < m; i++)
-  {
-    for (int j = 0; j < n; j++)
-    {
-      if (a[i][j] == 0)
-        counterZeros++; //Counting number of zeroes
+    for (int i = 0; i < m; i++) {
+        for (int j = 0; j < n; j++) {
+            if (a[i][j] == 0) counterZeros++;  // Counting number of zeroes
         }
     }
 
     // makes sure the matrix is a sparse matrix
-  if (counterZeros > ((m * n) / 2)) //Checking for sparse matrix
-    cout << "Sparse matrix";
+    if (counterZeros > ((m * n) / 2))  // Checking for sparse matrix
+        std::cout << "Sparse matrix";
     else
-    cout << "Not a sparse matrix";
+        std::cout << "Not a sparse matrix";
+
+    for (int i = 0; i < m; i++) delete[] a[i];
+    delete[] a;
+    return 0;
 }