how to pass a string as an argument to a sub fuction and what is the maximum limit of subscripts that the character array can hold as an argument in a function...

>> how to pass a string as an argument to a sub fuction

The same as you would any other data type

void foo( const char* some_string)
{
 }

int main()
{
     foo("Hello World");

     return 0;
}

>>what is the maximum limit of subscripts that the character array can hold

See limits.h for maximum value of a signed integer.