add relation solution

1 files changed, 101 insertions, 0 deletions

diff --git a/pract KN/week2/relation.cpp b/pract KN/week2/relation.cpp
new file mode 100644
index 0000000..ce4ea84
--- /dev/null
+++ b/pract KN/week2/relation.cpp
@@ -0,0 +1,101 @@
+#include<iostream>
+#include<fstream>
+
+struct pair {
+	int first;
+	int second;
+};
+
+pair makePair(int fst, int snd) {
+	return { fst, snd };
+}
+
+void initPair(pair& arg, int fst, int snd) {
+	arg.first = fst;
+	arg.second = snd;
+}
+
+const int MAX_SIZE = 25;
+
+struct relation {
+	pair data[MAX_SIZE];
+	int size = 0;
+};
+
+void addPair(relation& toAdd, const pair& p) {
+	if (toAdd.size > MAX_SIZE - 1)
+		return;
+	toAdd.data[toAdd.size++] = makePair(p.first, p.second);
+}
+
+void addPair(relation& toAdd, int first, int second) {
+	if (toAdd.size > MAX_SIZE - 1)
+		return;
+	toAdd.data[toAdd.size++] = makePair(first, second);
+}
+
+void writePair(const pair& p, std::ofstream& in) {
+	in << p.first << " " << p.second << std::endl;
+}
+
+pair readPair(std::ifstream& in) {
+	int first = 0;
+	int second = 0;
+	in >> first >> second;
+	return makePair(first, second);
+}
+
+void writeRelation(const relation& r) {
+	std::ofstream outFile("relation.txt");
+	if (outFile.bad())
+		return;
+
+	outFile << r.size << std::endl;
+
+	for (int i = 0; i < r.size; i++)
+		writePair(r.data[i], outFile);
+
+	outFile.close();
+}
+
+relation readRelation() {
+	std::ifstream inFile("relation.txt");
+
+	if (inFile.bad())
+		throw std::exception("Problem with reading the file");
+
+	relation toReturn;
+	int size = 0;
+	inFile >> size;
+
+	for (int i = 0; i < size; i++)
+		addPair(toReturn, readPair(inFile));
+
+	inFile.close();
+	return toReturn;
+}
+
+void printPair(const pair& p) {
+	std::cout << p.first << " " << p.second << std::endl;
+}
+
+void printRelation(const relation& r) {
+	for (int i = 0; i < r.size; i++)
+		printPair(r.data[i]);
+}
+
+int main() {
+	relation example;
+	// {{1, 2, 3, 4}, <}
+	addPair(example, 1, 2);
+	addPair(example, 1, 3);
+	addPair(example, 1, 4);
+	addPair(example, 2, 3);
+	addPair(example, 2, 4);
+	addPair(example, 3, 4);
+
+	printRelation(example);
+	std::cout << std::endl;
+	writeRelation(example);
+	printRelation(readRelation());
+}