View Compilation Error

0_0_32675569_1867.cpp: In function 'int main()':
0_0_32675569_1867.cpp:41:33: error: 'strlen' was not declared in this scope
    for (int k = 0; k < strlen(ss); k++)
                                 ^
0_0_32675569_1867.cpp:53:23: error: 'strlen' was not declared in this scope
   else if(ss[strlen(ss)-1]==')')
                       ^