Command Line Parameters are the ones which are supplied at the
beginning of a program. Most of the old day DOS programs will display a list
of matching parameters, if the program call is supplied with -help
parameter. This -help command will also be a command line parameter
for the program instructing it to display the help note.
In C++, the command line parameters are
supplied as like other language programs. Internally the two
parameters of the c++ main() function will be used to decipher the values.
They are named as argc and argv by convention.
The argc is the first parameter of type int. This
supplies the number of commands/words that occurred in the program
invocation. If the program is called with 2 parameters this will have a
value of 3. This includes the program name in addition to the two
parameters.
The argv[] is a character array holding each parameter
value at one array. Usually the number of the values in this argv[] array is
determined using the argc parameter and the values are pulled accordingly.
The following sample shows how to supply parameters to
a console c++ program and print them.
#include <iostream.h>
void main(int argc, char *argv[])
{
for(int i=0; i < argc; i++)
cout<<argv[i]<<endl;
}
These command line parameters can be used in
any program. Usually console program requiring inputs of
server names and other application initialization parameters
can be benefited by using these command line parameters.