The main Function
Every program must have a function in the global namespace
called main
, which is the main
program. This function must return type int
. The C++ environment calls main
; your program must never call main
. The main
function cannot be declared inline
or static
. It can be called with no arguments or
with two arguments:
int main( )
or:
int main(int argc, char* argv[])
The argc
parameter is the
number of command-line arguments, and argv
is an array of pointers to the
command-line arguments, which are null-terminated character strings. By
definition, argv[argc]
is a null
pointer. The first element of the array (argv[0]
) is the program name or an empty
string.
Tip
An implementation is required to support at least two forms of
main
: one that takes no parameters,
and one that takes the two parameters for command-line arguments. An
implementation can support other forms of main
. The standard recommends that the first
two parameters should be the same as they are in the standard, and
that additional parameters follow them.
Static objects at namespace scope can have constant or dynamic initial values, those of POD type with constant values are initialized by constant data before the program ...
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