Add C++ solution to challenge 006

2 files changed, 78 insertions, 0 deletions

diff --git a/challenge-006/paulo-custodio/cpp/ch-1.cpp b/challenge-006/paulo-custodio/cpp/ch-1.cpp
new file mode 100644
index 0000000000..314584f1f9
--- /dev/null
+++ b/challenge-006/paulo-custodio/cpp/ch-1.cpp
@@ -0,0 +1,45 @@
+/*
+Challenge 006
+
+Challenge #1
+Create a script which takes a list of numbers from command line and print the
+same in the compact form. For example, if you pass "1,2,3,4,9,10,14,15,16"
+then it should print the compact form like "1-4,9,10,14-16".
+*/
+
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+using namespace std;
+
+vector<int> nums;
+
+void parse_nums(const string& str) {
+    istringstream iss(str);
+    string num_str;
+    while (getline(iss, num_str, ',')) {
+        int num = atoi(num_str.c_str());
+        nums.push_back(num);
+    }
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 2) return EXIT_FAILURE;
+    parse_nums(argv[1]);
+    for (size_t i = 0; i < nums.size(); i++) {
+        cout << nums[i];
+        if (i + 2 < nums.size() &&
+            nums[i + 1] == nums[i] + 1 &&
+            nums[i + 2] == nums[i] + 2) {
+            size_t j = 0;
+            while (i + j < nums.size() && nums[i + j] == nums[i] + j)
+                j++;
+            i += j - 1;
+            cout << "-" << nums[i];
+        }
+        if (i + 1 < nums.size())
+            cout << ",";
+    }
+    cout << endl;
+}
diff --git a/challenge-006/paulo-custodio/cpp/ch-2.cpp b/challenge-006/paulo-custodio/cpp/ch-2.cpp
new file mode 100644
index 0000000000..b408b41945
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+++ b/challenge-006/paulo-custodio/cpp/ch-2.cpp
@@ -0,0 +1,33 @@
+/*
+Challenge 006
+
+Challenge #2
+Create a script to calculate Ramanujan's constant with at least 32 digits of
+precision. Find out more about it here.
+
+The standard IEEE 754 double-precision binary floating-point format: binary64
+gives only 15 to 17 significant decimal digits
+*/
+
+#include <iostream>
+#include <gmp.h>
+#include <mpfr.h>
+
+int main() {
+    mpfr_set_default_prec(256);  // 107 bits needed to represent 32 decimal digits
+
+    mpfr_t pi, e, k;
+    mpfr_inits(pi, e, k, NULL);
+
+    mpfr_const_pi(pi, MPFR_RNDN);
+
+    mpfr_set_str(e, "163", 10, MPFR_RNDN);  // e = 163
+    mpfr_sqrt(e, e, MPFR_RNDN);             // e = sqr(163)
+    mpfr_mul(e, pi, e, MPFR_RNDN);          // e = pi*sqr(163)
+
+    mpfr_exp(k, e, MPFR_RNDN);              // k = e^(pi*sqr(163))
+
+    mpfr_printf("%32.12Rf\n", k);           // 18.12 = 32 precision
+
+    mpfr_clears(pi, e, k, NULL);
+}