View Compilation Error

0_0_17016355_18341.cpp: In function 'int KM()':
0_0_17016355_18341.cpp:33:27: error: 'memset' was not declared in this scope
     memset(dx,0,sizeof(dx));
                           ^
0_0_17016355_18341.cpp: In function 'int pipei(char*, char*)':
0_0_17016355_18341.cpp:66:15: error: 'strlen' was not declared in this scope
     j=strlen(a)-1;len=strlen(b);
               ^