Defined in header
#define assert(condition) ((void)0)
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) compares equal to zero. If it does,
assert outputs implementation-specific diagnostic information on the standard error output and calls std::abort. The diagnostic information is required to include the text of
expression, as well as the values of the standard macros __FILE__, __LINE__, and the standard variable __func__.
|condition||-||expression of scalar type|
 Return value
Execution continues past the first assert test: test.cc:10: int main(): Assertion `2+2==5' failed. Aborted
 See also
|static assertion||performs compile-time assertion checking (since C++11)|
| causes abnormal program termination (without cleaning up)
C documentation for assert