Show me the steps to solve Coding Instructions: Write a one$-$dimensional finite element code in C$++$ using the deal.II FEM library frameswork and the template provided to solve the given problem, following these requirements: $$ Code $($a$)$ linear, $($b$)$ quadratic and $($c$)$ cubic order Lagrange polynomial basis functions. $$ Include a function to calculate the L $2$ norm of the error between the finite element solution $($u h $)$ with the exact solution $($u$),$ given by qR $($u $$ u h$)2$ dx$.$ All integration in Klocal, Flocal, and the L$2$ norm of the error should be done by Gaussian quadrature $($see Lecture $4\mathrm{.}11),$ instead of using the analytical solution to the integrals shown in the lectures. $$ For submission, use a $100$ element mesh. $($You will be provided with the six $.$vtk solution files for a $10$ element mesh to help you debug your code. A table of the corresponding L $2$ norms is included at the end of the instructions.$)$ You will be provided with four files to create and run your code $($please refer to the recorded tutorials for an in$-$depth explanation$)$: $$ main$1.$cc $($the source file that defines and solve the boundary value problem using your C$++$ class$)$ FEM$1.$h $($the template header file defining your finite element method C$++$ class$)$ writeSolutions.h $($used to create the solution files you will submit$)$ CMakeLists.txt $($used to create a Makefile to run your code, as shown in the first segment of the recorded introduction to C$++)$