View Compilation Error

0_0_33198430_27533.cpp: In function 'Vector Rotate(Vector, double)':
0_0_33198430_27533.cpp:19:25: error: 'c' was not declared in this scope
     return Vector(A.x * c
                         ^
0_0_33198430_27533.cpp:19:25: error: expected ';' at end of input
0_0_33198430_27533.cpp:19:25: error: expected '}' at end of input