A flow chart is just one aspect of a program’s design. Notably absent from what a flow chart represents is the design of the data structures used by the program. Also, a flow chart typically describes a single subprogram (function or subroutine), the relationship between the subprograms is represented by a structure chart (who calls who). Of course if your program is so simple that it only has one subprogram (main for example in a C program), then the structure chart is trivial since there are no calling relationships.