g++: add page (#1718)

pages/common/g++.md

@@ -0,0 +1,20 @@
+# gplusplus
+
+> Compiles C++ source files.
+> Part of GCC (GNU Compiler Collection).
+
+- Compile a source code file into an executable binary:
+
+`g++ {{source.cpp}} -o {{output_executable}}`
+
+- Display (almost) all errors and warnings:
+
+`g++ {{source.cpp}} -Wall -o {{output_executable}}`
+
+- Choose a language standard to compile for(C++98/C++11/C++14/C++17):
+
+`g++ {{source.cpp}} -std={{language_standard}} -o {{output_executable}}`
+
+- Include libraries located at a different path than the source file:
+
+`g++ {{source.cpp}} -o {{output_executable}} -I{{header_path}} -L{{library_path}} -l{{library_name}}`