View Compilation Error

0_0_21593466_8390.cpp: In function 'int Analyse(char*, int*)':
0_0_21593466_8390.cpp:20:22: error: 'strlen' was not declared in this scope
      while(i<strlen(s))
                      ^
0_0_21593466_8390.cpp: In function 'int main()':
0_0_21593466_8390.cpp:70:23: error: 'strcmp' was not declared in this scope
        if(strcmp(a,"0")==0&&strcmp(b,"0")==0)
                       ^