Comparing the execution speed of C++ and VB is not an accurate representation of language speeds. What your really comparing, most likely, is the ability of the various compilera to generate efficient code, and to apply various optimizations with respect to performance. In short, its not the language that determines execution speed, but the compiler. Its quite likely that the same code, compiled with the Borland C++ compiler will not have the same execution speed of the identical C++ program compiled with the MS Visual C++ Compiler.
That being said, what really provides performance capabilities with C, that VB does not provide, are for example, some of the following programming capabilities:
Ability to to write inline assembler code
Store variables in registers
Pointer manipulation
Shuffle pointers rather than shuffle values
Pointer based string manipulation functions
and others things as well. On the flip side, code development and maintenance are usually easier with VB. Good Luck
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As a circle of light increases so does the circumference of darkness around it. - Albert Einstein