idk

Makefile

@@ -1,4 +1,5 @@
 CC := clang++ -Wall -std=c++17 -Wall -Wextra -g -fsanitize=address,undefined -fno-omit-frame-pointer
+#CC := clang++ -Wall -std=c++17 -Wall -Wextra
 
 setup:
 	mkdir build
@@ -39,6 +40,11 @@ sheet06:
 	chmod +x build/sheet06
 	build/sheet06
 
+sheet07:
+	$(CC) src/sheet07.cpp -o build/sheet07
+	chmod +x build/sheet07
+	build/sheet07
+
 pizza:
 	$(CC) src/pizza.cpp -o build/pizza
 	chmod +x build/pizza

src/sheet06.cpp

@@ -55,9 +55,10 @@ void bubble_sort(std::vector<T> &v, std::function<bool(T,T)> predicate)
 	}while(has_swapped);
 }
 
-char add()
+template<typename A>
+A add(A a)
 {
-	return 0;
+	return a;
 }
 
 template<typename A, typename... Args>

src/sheet07.cpp

@@ -0,0 +1,139 @@
+#include <exception>
+#include<iostream>
+#include <ostream>
+#include <system_error>
+#include<vector>
+#include<initializer_list>
+#include<stdexcept>
+
+template<typename T>
+class matrix
+{
+	public:
+		matrix(size_t rows, size_t columns) : rows(rows), columns(columns)
+		{
+			data();
+		}
+		matrix(size_t rows, size_t columns, const T &ival) : rows(rows), columns(columns)
+		{
+			data = std::vector<T>(rows*columns, ival);
+		}
+		matrix(std::initializer_list<std::initializer_list<T>> imat)
+		{
+			size_t prev_length;
+			for(std::initializer_list<T> row : imat)
+			{
+				if(prev_length!=row.size())
+				{
+					throw std::domain_error("provided initializer list with empty spots.");
+				}
+
+				prev_length = row.size();
+
+				for(T t : row)
+				{
+					data.push_back(t);
+				}
+			}
+		}
+		T& operator() (size_t row, size_t column)
+		{
+			if(row>=this->num_rows())
+			{
+				throw std::length_error("row outside matrix.");
+			}
+			if(column>=this->num_columns())
+			{
+				throw std::length_error("column outside matrix.");
+			}
+
+			return data.at(row*(this->num_columns())+column);
+		}
+		const T& operator() (size_t row, size_t column) const
+		{
+			if(row>=this->num_rows())
+			{
+				throw std::length_error("row outside matrix.");
+			}
+			if(column>=this->num_columns())
+			{
+				throw std::length_error("column outside matrix.");
+			}
+
+			return data.at(row*(this->num_columns())+column);
+		}
+
+		size_t num_elements() const noexcept { return columns*rows; }
+		size_t num_rows() const noexcept { return rows; }
+		size_t num_columns() const noexcept { return columns; }
+
+		friend matrix operator* (const matrix &lhs, const T &scale)
+		{
+			matrix out(lhs.num_rows(), lhs.num_columns(), 0);
+			for(size_t x=0; x<lhs.num_columns(); ++x)
+			{
+				for(size_t y=0; y<lhs.num_rows(); ++y)
+				{
+					out(y,x) = lhs(y,x)*scale;
+				}
+			}
+			return out;
+		}
+
+		friend matrix operator* (const matrix &lhs, const matrix &rhs)
+		{
+			//TODO
+			throw std::logic_error("unimplemented");
+		}
+
+		friend bool operator== (const matrix &lhs, const matrix &rhs)
+		{
+			if(lhs.num_columns() != rhs.num_columns() || lhs.num_rows() != rhs.num_rows())
+			{
+				return false;
+			}
+
+			for(size_t x=0; x<lhs.num_columns(); ++x)
+			{
+				for(size_t y=0; y<lhs.num_rows(); ++y)
+				{
+					if(lhs(y,x)!=rhs(y,x))
+					{
+						return false;
+					}
+				}
+			}
+			return true;
+		}
+
+		friend bool operator!=(const matrix &lhs, const matrix &rhs)
+		{
+			return !(lhs==rhs);
+		}
+
+		friend std::ostream& operator<< (std::ostream &os, const matrix &m)
+		{
+			for(size_t x=0; x<m.num_columns(); ++x)
+			{
+				for(size_t y=0; y<m.num_rows(); ++y)
+				{
+					os << m(y,x) << '\t';
+				}
+				os << '\n';
+			}
+			return os;
+		}
+
+	private:
+		size_t rows;
+		size_t columns;
+		std::vector<T> data;
+};
+
+int main()
+{
+	matrix<int> m(5,5,5);
+	std::cout << m;
+	std::cout << m*5;
+	std::cout << m*m;
+}