View Compilation Error

0_0_14946954_4360.cpp: In function 'int main()':
0_0_14946954_4360.cpp:15:23: error: 'strlen' was not declared in this scope
         len=strlen(s+1);
                       ^
0_0_14946954_4360.cpp:18:23: error: incompatible types in assignment of 'int' to 'int [1200]'
         counter[len+1]=0;
                       ^