View Compilation Error

0_0_17384701_17803.cpp: In function 'void dijk(int)':
0_0_17384701_17803.cpp:30:29: error: 'memset' was not declared in this scope
     memset(vis,0,sizeof(vis));
                             ^
0_0_17384701_17803.cpp: In function 'int main()':
0_0_17384701_17803.cpp:56:29: error: 'memset' was not declared in this scope
         memset(G,0,sizeof(G));
                             ^