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-rw-r--r--challenge-008/paulo-custodio/cpp/ch-1.cpp67
-rw-r--r--challenge-008/paulo-custodio/cpp/ch-2.cpp38
2 files changed, 105 insertions, 0 deletions
diff --git a/challenge-008/paulo-custodio/cpp/ch-1.cpp b/challenge-008/paulo-custodio/cpp/ch-1.cpp
new file mode 100644
index 0000000000..9915f46bb8
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+++ b/challenge-008/paulo-custodio/cpp/ch-1.cpp
@@ -0,0 +1,67 @@
+/*
+Challenge 008
+
+Challenge #1
+Write a script that computes the first five perfect numbers. A perfect number
+is an integer that is the sum of its positive proper divisors (all divisors
+except itself). Please check Wiki for more information. This challenge was
+proposed by Laurent Rosenfeld.
+*/
+
+#include <iostream>
+using namespace std;
+
+bool is_prime(int n) {
+ if (n <= 1)
+ return false;
+ if (n <= 3)
+ return true;
+ if ((n % 2) == 0 || (n % 3) == 0)
+ return false;
+ for (int i = 5; i * i <= n; i += 6)
+ if ((n % i) == 0 || (n % (i + 2)) == 0)
+ return false;
+ return true;
+}
+
+int next_prime(int n) {
+ if (n <= 1)
+ return 2;
+ do {
+ n++;
+ } while (!is_prime(n));
+ return n;
+}
+
+int ipow(int base, int exp) {
+ int result = 1;
+ for (;;) {
+ if (exp & 1)
+ result *= base;
+ exp >>= 1;
+ if (!exp)
+ break;
+ base *= base;
+ }
+ return result;
+}
+
+// Euclid proved that 2 ^ (p-1) * (2 ^ p - 1) is an even perfect number
+// whenever 2^p - 1 is prime
+int next_perfect(void) {
+ static int p = 1;
+ while (true) {
+ p = next_prime(p);
+ int f = ipow(2, p) - 1;
+ if (is_prime(f))
+ return ipow(2, p - 1) * f;
+ }
+}
+
+int main(int argc, char* argv[]) {
+ int n = 5;
+ if (argc == 2)
+ n = atoi(argv[1]);
+ for (int i = 0; i < n; i++)
+ cout << next_perfect() << endl;
+}
diff --git a/challenge-008/paulo-custodio/cpp/ch-2.cpp b/challenge-008/paulo-custodio/cpp/ch-2.cpp
new file mode 100644
index 0000000000..aeca0d65e4
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+++ b/challenge-008/paulo-custodio/cpp/ch-2.cpp
@@ -0,0 +1,38 @@
+/*
+Challenge 008
+
+Challenge #2
+Write a function, ‘center’, whose argument is a list of strings, which will
+be lines of text. The function should insert spaces at the beginning of the
+lines of text so that if they were printed, the text would be centered, and
+return the modified lines.
+*/
+
+#include <iostream>
+#include <vector>
+#include <string>
+using namespace std;
+
+void center(vector<string>& lines) {
+ size_t max_len = 0;
+
+ for (auto& line : lines)
+ if (line.size() > max_len)
+ max_len = line.size();
+
+ for (auto& line : lines)
+ line = string((max_len - static_cast<int>(line.size())) / 2, ' ') + line;
+}
+
+int main(int argc, char* argv[]) {
+ argc--; argv++;
+
+ vector<string> lines;
+ for (int i = 0; i < argc; i++)
+ lines.push_back(argv[i]);
+
+ center(lines);
+
+ for (auto& line : lines)
+ cout << line << endl;
+}