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.