View Compilation Error

0_0_17959575_16598.cpp: In function 'int main()':
0_0_17959575_16598.cpp:15:29: error: 'memset' was not declared in this scope
         memset(b,0,sizeof(b));
                             ^
0_0_17959575_16598.cpp:16:21: error: 'sizeofc' was not declared in this scope
          memset(c,0,sizeofc));
                     ^