View Compilation Error

0_0_29296164_26234.cpp: In function 'bool operator<(str, str)':
0_0_29296164_26234.cpp:12:30: error: 'strcmp' was not declared in this scope
         if(strcmp(ne1.s,ne2.s)==1)
                              ^
0_0_29296164_26234.cpp: In function 'int GetNum(char*)':
0_0_29296164_26234.cpp:27:31: error: 'strlen' was not declared in this scope
     for(int i = 0;i < strlen(t); ++i){
                               ^
0_0_29296164_26234.cpp: In function 'int main()':
0_0_29296164_26234.cpp:58:33: error: 'memset' was not declared in this scope
         memset(map,0,sizeof(map));
                                 ^
0_0_29296164_26234.cpp:64:33: error: 'strcpy' was not declared in this scope
             strcpy(st[n1].s,str1);
                                 ^