View Compilation Error

0_0_21433321_1993.cpp: In function 'int main()':
0_0_21433321_1993.cpp:18:15: error: redeclaration of 'int j'
   for(int j=n,j=m;i;i--){
               ^
0_0_21433321_1993.cpp:18:11: note: 'int j' previously declared here
   for(int j=n,j=m;i;i--){
           ^
0_0_21433321_1993.cpp:18:19: error: 'i' was not declared in this scope
   for(int j=n,j=m;i;i--){
                   ^