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66 lines
1.8 KiB
66 lines
1.8 KiB
#include <iostream>
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#include <string>
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#include <vector>
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#include <cmath>
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// use generics for a reusable method
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template <typename number>
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std::string create_overflow() {
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number next = 2;
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number valid = 0;
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number iter = 0;
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while(true) {
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next = next * 2;
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if(valid > next) {
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std::string message = typeid(number).name();
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message += " overflow occurred: 2**" + std::to_string(iter) + " = " + std::to_string(next);
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message += " should be bigger as 2**" + std::to_string(iter - 1) + " != " + std::to_string(valid);
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return message;
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}
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iter++; valid = next;
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}
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}
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std::vector<bool> sieve_of_eratosthenes(int limit) {
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// avoid edge cases limit=0 or limit=1
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int length = limit + 2;
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// preparation of a bool vector
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std::vector<bool> primes(length, true);
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primes[0] = false;
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primes[1] = false;
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// calculate sieve
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for(int i = 2; i <= std::sqrt(limit); i++) {
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if(primes[i]) {
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for(int p = i * i; p <= limit; p += i) {
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primes[p] = false;
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}
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}
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}
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return primes;
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}
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/*
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* Anmerkung:
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* Ich mag es nicht wirklich Pointer in C++ zu benutzen. Deshalb verwende ich die Klassen std::string und std::vector
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* um zu verhindern, dass die Funktionen bool* bzw. char* pointer ausgeben müssen.
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*/
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int main() {
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std::cout << create_overflow<short>() << std::endl;
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std::cout << create_overflow<int>() << std::endl;
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std::cout << create_overflow<long>() << std::endl;
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int limit = 100;
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std::vector<bool> primes = sieve_of_eratosthenes(limit);
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std::cout << "Prime numbers up to " << limit << " are: ";
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for (int i = 0; i < limit; ++i) {
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if (primes[i]) {
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std::cout << i << " ";
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}
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}
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std::cout << std::endl;
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return 0;
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} |