Describing the relevance of linear approximation in a variety of fields, Numerical Linear Approximation in C presents a unique collection algorithm, linear approach that can be used to analyze, model, and compress discrete data. The final section presents solutions to underdetermined consistent system of linear equations which have different constraints on the elements of the vector solution in mind. Except at the beginning, all chapters include the functions C of the algorithm, along with drivers that contain examples of various test case results.