Defined in header <cassert> #ifdef NDEBUG
#define assert(condition) ((void)0)
#else
#define assert(condition) /*implementation defined*/
#endif
The definition of the macro assert depends on another macro, NDEBUG, which is not defined by the standard library.
If NDEBUG is defined as a macro name at the point in the source code where <cassert> is included, then assert does nothing.
If NDEBUG is not defined, then assert checks if its argument (which must have scalar type