/in/foo.cc: In function 'int main()':
/in/foo.cc:17:4: error: 'p' was not declared in this scope
    p[i]=x*c[1];
    ^
/in/foo.cc:21:4: error: 'p' was not declared in this scope
    p[i]=x*c[2];
    ^
/in/foo.cc:25:4: error: 'p' was not declared in this scope
    p[i]=x*c[3];
    ^