View Compilation Error

0_0_14734888_9952.cpp: In function 'bool spfa()':
0_0_14734888_9952.cpp:29:27: error: 'memset' was not declared in this scope
  memset(dis,-1,sizeof(dis));
                           ^
0_0_14734888_9952.cpp: In function 'int main()':
0_0_14734888_9952.cpp:83:30: error: 'memset' was not declared in this scope
   memset(head,-1,sizeof(head));
                              ^
0_0_14734888_9952.cpp:88:8: error: 'i' was not declared in this scope
   for( i=1;i<=r;i++){
        ^