View Compilation Error

0_0_35975804_3570.cpp: In function 'int main()':
0_0_35975804_3570.cpp:73:12: error: 'din' was not declared in this scope
            din[b]++;
            ^
0_0_35975804_3570.cpp:75:10: error: redeclaration of 'int a'
      int a = 0, b = 0;
          ^
0_0_35975804_3570.cpp:70:17: note: 'int a' previously declared here
             int a = id[i], b = id[k];
                 ^
0_0_35975804_3570.cpp:75:17: error: redeclaration of 'int b'
      int a = 0, b = 0;
                 ^
0_0_35975804_3570.cpp:70:28: note: 'int b' previously declared here
             int a = id[i], b = id[k];
                            ^
0_0_35975804_3570.cpp:78:14: error: 'din' was not declared in this scope
         if (!din[i]) a ++ ;
              ^