This document describes a C program written by Salar Delavar Qashqai to analyze the geometric and material nonlinearity of a 2D truss structure under force and ductility damage index control. The program imports input data files, performs a pushover analysis using incremental loading, calculates member forces and displacements, and exports output to text, Excel, MATLAB, and HTML files. Key sections of code are presented to demonstrate how the program assembles and solves the system stiffness matrix, calculates element forces and stiffness, and checks for convergence at each iteration.