View Compilation Error

0_0_21230310_14121.cpp: In function 'bool check(char*)':
0_0_21230310_14121.cpp:9:24: error: 'strlen' was not declared in this scope
      int i,len=strlen(c);
                        ^
0_0_21230310_14121.cpp: In function 'int main()':
0_0_21230310_14121.cpp:29:29: error: 'memset' was not declared in this scope
         memset(m,0,sizeof(m));
                             ^
0_0_21230310_14121.cpp:32:31: error: 'strlen' was not declared in this scope
             for(j=0;j<strlen(s);j++)
                               ^