View Compilation Error

0_0_16209324_10962.cpp: In function 'void init()':
0_0_16209324_10962.cpp:4:9: error: 'a' was not declared in this scope
  memset(a, 0, sizeof(a));
         ^
0_0_16209324_10962.cpp:4:24: error: 'memset' was not declared in this scope
  memset(a, 0, sizeof(a));
                        ^