View Compilation Error

0_0_26987690_13485.cpp: In function 'int main()':
0_0_26987690_13485.cpp:5:9: error: expected initializer before '.' token
  float a.b.x.y;
         ^
0_0_26987690_13485.cpp:7:12: error: 'a' was not declared in this scope
 while(cin>>a>>b>>x>>y)
            ^
0_0_26987690_13485.cpp:7:15: error: 'b' was not declared in this scope
 while(cin>>a>>b>>x>>y)
               ^
0_0_26987690_13485.cpp:7:18: error: 'x' was not declared in this scope
 while(cin>>a>>b>>x>>y)
                  ^
0_0_26987690_13485.cpp:7:21: error: 'y' was not declared in this scope
 while(cin>>a>>b>>x>>y)
                     ^
0_0_26987690_13485.cpp:9:33: error: 'sqrt' was not declared in this scope
   d=sqrt((a-b)*(a-b)+(x-y)*(x-y));
                                 ^