View Compilation Error

0_0_32446748_3270.cpp: In function 'void cle(char*)':
0_0_32446748_3270.cpp:6:14: error: 'strlen' was not declared in this scope
  m = strlen(s);
              ^
0_0_32446748_3270.cpp: In function 'int main()':
0_0_32446748_3270.cpp:23:31: error: 'memset' was not declared in this scope
   memset(samp, 0, sizeof(samp));
                               ^
0_0_32446748_3270.cpp:32:23: error: 'strcmp' was not declared in this scope
     if (strcmp(ed,"ND")==0) {
                       ^
0_0_32446748_3270.cpp:46:23: error: 'strcmp' was not declared in this scope
     if (strcmp(ed,"ND")==0) {
                       ^
0_0_32446748_3270.cpp:53:23: error: 'strcmp' was not declared in this scope
   if (strcmp(res, samp) == 0) {
                       ^
0_0_32446748_3270.cpp:59:22: error: 'strcmp' was not declared in this scope
   if (strcmp(res,samp)==0) {
                      ^