View Compilation Error

0_0_26688472_26912.cpp: In function 'int main()':
0_0_26688472_26912.cpp:14:17: error: 'strlen' was not declared in this scope
   int l=strlen(a);
                 ^
0_0_26688472_26912.cpp:29:25: error: expected ')' before ';' token
      if(i<t) printf("\n";
                         ^