This thesis presents the concepts of structured programming and illustrates how they can be used to develop efficient and reliable programs and aid in language selection. Topics are presented and used to compare several languages with each other rather than with some abstract ideal. Structured design is a set of concepts that aids the decomposition of a problem using basic block structures into manageable subproblems. Decomposition is a process whereby the large problem is decomposed into components that can be easily understood. This process is continued until the smallest component can be represented by a unit of code performing a single action. By means of the four basic building blocks the atom, concatenation, selection, and repetition one can produce a correct well structured program. In addition, the top-down approach and/or the bottom up approach can assist in producing a structured program that is easy to design, code, debug, modify, and maintain. These approaches minimize the number of bugs and the time spent in the debugging process. Various testing techniques supporting the structured programming process are presented to aid in determining a program's correctness. The languages must support structured programming. Microsoft FORTRAN, Microsoft QuickBASIC, Turbo Pascal, and Microsoft C are analyzed and compared on the basis of syntactic style, semantic structure, data types and manipulation, application facilities, and application requirements. Example programs are presented to reinforce these concepts. Frame programs are developed in these languages and are used to assist in the language evaluation. / Master of Science