unary plus

[cengineer]

I have rewritten bjarne stroustrup's calculator program to accept input from a file and parse it and evaluate it. Everything works fine except for the instance where the plus sign acts as a signed value. For example 3*+2.5 equals 7.5 but the program expects a parenthesis. How can I implement the change?

 }
	  case MINUS :			// unary minus
	        return -prim(true);
	  case LP :
	  {
	        double e = expr(true);
	        if (curr_tok != RP) return error("')' expected");
	        get_token();			//eat ')'
	        return e;
	  }

This is what is applied when a unary minus is used but I cannot add a unary plus statement since it creates an error that plus is already used.

[Bazzy]

Don't double post http://www.cplusplus.com/forum/beginner/16496/#msg82511

[cengineer]

Sorry; mistake. Thanks for your help.