View Compilation Error

0_0_35434769_10065.cpp: In function 'int main()':
0_0_35434769_10065.cpp:22:13: error: 'x' was not declared in this scope
     s+=0.5*(x[i]*y[i+1]-x[i+1]*y[i]);
             ^
0_0_35434769_10065.cpp:22:18: error: 'y' was not declared in this scope
     s+=0.5*(x[i]*y[i+1]-x[i+1]*y[i]);
                  ^
0_0_35434769_10065.cpp:24:12: error: 'x' was not declared in this scope
    s+=0.5*(x[n-1]*y[0]-x[0]*y[n-1]);
            ^
0_0_35434769_10065.cpp:24:19: error: 'y' was not declared in this scope
    s+=0.5*(x[n-1]*y[0]-x[0]*y[n-1]);
                   ^