View Compilation Error

0_0_20291340_7599.cpp: In function 'int main()':
0_0_20291340_7599.cpp:7:24: error: 'strcmp' was not declared in this scope
         if(strcmp(s,"0")==0)   break;  
                        ^
0_0_20291340_7599.cpp:8:21: error: 'strlen' was not declared in this scope
     int len=strlen(s);    
                     ^