Changed the Makefile to reference the C++ compiler, rather than the C compiler

Makefile

@@ -1,8 +1,8 @@
 all:
-	cc *.cpp -O3 -Wall -Wextra -std=c++17 -o lottery
+	cxx *.cpp -O3 -Wall -Wextra -std=c++17 -o lottery
 
 compile:
-	cc *.cpp -O3 -c
+	cxx *.cpp -O3 -c
 
 debug:
-	cc *.cpp -g -std=c++17 -o calculator -lstdc++ -lm
+	cxx *.cpp -g -std=c++17 -o calculator -lstdc++ -lm