writing a code that can integrate data pointsof shear force on beam stored in matrix to get data points of moment using trapezoidal method but without using functions

i have a project to create a code that can calculate the deflection of a beam,i use the method of section from applied mechanics to geth the equations of shear forces then calculated my shear force distributions and saved them in a matrix of 2001X2, our lecture told us not to use any functions in this project . now i want to create a code that can integrate the matrix of the shear force to get moments. he said we can use trapezodial rule to do that (not the function of trapz or cumtrapz) . i have to integrate the matrix of shear force to get moment then integrate the matrix of moment to slope then integrate the matrix of slope to get deflection.

thank you