View Compilation Error

0_0_28628156_16973.cpp: In function 'int main()':
0_0_28628156_16973.cpp:37:12: error: 'k' was not declared in this scope
         if(k==0) printf("Case %d: 0\n",cas);
            ^
0_0_28628156_16973.cpp:40:25: error: redeclaration of 'int k'
             int a,b,c,d,k;
                         ^
0_0_28628156_16973.cpp:37:12: note: '<typeprefixerror>k' previously declared here
         if(k==0) printf("Case %d: 0\n",cas);
            ^