This paper presents an algorithm for a program code for the analysis of concrete columns reinforced with non-prestressed reinforcement, prestressed reinforcement or both. The algorithm can be used to generate the co-ordinates of the load-moment interaction diagram for the section chosen in terms of shape, material properties, type, amount and location of nonprestressed and prestressed reinforcement. Three shapes, namely rectangular, T, and I can be analyzed. Hollow core wall panels can be analyzed by converting them to equivalent I sections. The lateral reinforcement could he ties, spirals or none. The program can also he coded to reanalyze the section for revised partial input. This capability aids the designer to generate the loads and moments for say a different compressive strength of concrete without reinputing the entire design data. The load-moment values can be printed to look like the load-moment interaction diagram. The various assumptions involved, the equations, and the sequence of calculations are explained using a number of flow charts. A procedure is outlined for using the program for design purposes. Example problems are provided to illustrate the input - output variables. The program code, written in BASIC for Apple desktop computer can be obtained from the author. The algorithm deals with only the strength aspect. The serviceability aspect, especially for prestressed columns should be checked seperately.