expression-cannot-be-used-as-a-function

[1033SN]

so i see this error constantly,here is my code, can someone help me please?thanks in advance

#include <iostream> 
using namespace std; 
class area 
{ 
 
 public: 
 float  Area ,length, width, Perimeter,sqrt,coordinates;
 float P1, P2, P3, P4;  
 int x1,x2,x3,x4,y1,y2,y3,y4; 
 

{
  
P1=0; 
P2=0; 
P3=0; 
width=1; 
length=1; 
coordinates=0; 
Area=0; 
Perimeter=0;
 } 
 void setcoordinates()
  { 
  Rectangle:
   cout<<"enter value of coordinates x1,x2,x3,x4,y1,y2,y3,y4"<<endl; 
   cin>>x1>>x2>>x3>>x4>>y1>>y2>>y3>>y4;
    P1 = sqrt((x2 - x1)*(x2 - x1) + (y2 - y1)*(y2 - y1)); 
	P2 = sqrt((x4 - x3)*(x4 - x3) + (y4 - y3)*(y4 - y3)); 
	P3 = sqrt((x3 - x2)*(x3 - x2) + (y3 - y2)*(y3 - y2)); 
	if (x1>0,x2>0,x3>0,x4>0,y1>0,y2>0,y3>0,y4>0)
	 {
	  cout<<"Rectangle in 1st Coordinate"<<endl;
	   }
	    else {
		 cout<<"Rectangle is not in 1st coordinate"<<endl;
		 goto Rectangle; 
		 } 
		 if(P1!=P2) 
		 { 
		 cout<<"Rectangle is not valid"; goto Rectangle;
		  } 
		  }
		  
void setwidth()

 
 { Rectangle:
  cout<<"width of rectangle: ";
   width=P1; 
   cout<<width; 
   cout<<endl; 
   if( width>20)
    { 
	cout<<"width is greater than 20"; 
	goto Rectangle; 
	} 
	
	else if (width <=0) 
	{ 
	cout<<"width is equal or less than 0"<<endl;
	 goto Rectangle;
	  } 
	  } 
void setlength()
 {
  Rectangle:
   cout<<"length of rectangle: "; 
   length=P3;
    cout<<length; 
	cout<<endl; 
if(length>20)
 {
  cout<<"length is greater than 20."<<endl; 
  goto Rectangle;
   }
    else if(length<=0) 
	{
	 cout<<"length is equal or less than 0."<<endl; 
	 goto Rectangle;
	  } 
	  }
	  
	  void calculate() 
	  {
	   Area=width*length; 
	   Perimeter=2*width+2*length;
	  }
	  
	   void show()
	    { 
		cout<<"width and length are less than 20 and greater than 0." <<endl; 
		cout<<"Area of rectangle = "<<Area<<endl;
		 cout<<"Perimeter of rectangle = "<<Perimeter<<endl;
		  if(P1=P3)
		   {
		    cout<<"it is a Square"<<endl;
			 } 
			 else
			  { cout<<"it is not a square";
			   }
			    }
				 };

 
int main()
 {
  Rectangle: 
  area c; 
  c.setcoordinates();
   c.setwidth(); 
   c.length(); 
   c.calculate();
    c.show(); 
	return 0; 
	}

[weaknessforcats]

What is this:

{
  
P1=0; 
P2=0; 
P3=0; 
width=1; 
length=1; 
coordinates=0; 
Area=0; 
Perimeter=0;
 }

It's not a function. It's a declared scope so anything done between the braces is deleted at the end of the scope. Probably this is what the compiler is trying to tell you.