View Compilation Error

0_0_33887805_15444.cpp: In function 'int main()':
0_0_33887805_15444.cpp:16:28: error: 'strlen' was not declared in this scope
         string str[strlen(a)];
                            ^
0_0_33887805_15444.cpp:24:17: error: 'str' was not declared in this scope
                 str[i]="(";
                 ^
0_0_33887805_15444.cpp:38:21: error: 'str' was not declared in this scope
                     str[kd.front()]="(";
                     ^
0_0_33887805_15444.cpp:46:17: error: 'str' was not declared in this scope
                 str[i]=")";
                 ^
0_0_33887805_15444.cpp:54:13: error: 'str' was not declared in this scope
             str[wz]="(";
             ^
0_0_33887805_15444.cpp:70:20: error: 'str' was not declared in this scope
                 if(str[i].empty()==false)
                    ^