View Compilation Error

0_0_37658071_16317.cpp: In function 'int dijstra(int)':
0_0_37658071_16317.cpp:35:35: error: 'memset' was not declared in this scope
  memset(dis,0X7F7F7F7F,sizeof(dis));
                                   ^
0_0_37658071_16317.cpp: In function 'int spfa(int)':
0_0_37658071_16317.cpp:65:29: error: 'memset' was not declared in this scope
  memset(dis,0X7F,sizeof(dis));
                             ^
0_0_37658071_16317.cpp: In function 'int main()':
0_0_37658071_16317.cpp:127:23: error: 'strlen' was not declared in this scope
    if(buf2[strlen(buf2)-1]=='>'){
                       ^