View Compilation Error

0_0_38382865_19869.cpp: In function 'int main()':
0_0_38382865_19869.cpp:7:25: error: 'n' was not declared in this scope
     while (scanf("%d", &n) != EOF)
                         ^
0_0_38382865_19869.cpp:11:14: error: 'i' was not declared in this scope
         for (i = 0 ; i < n ; i++)
              ^
0_0_38382865_19869.cpp:14:18: error: 'j' was not declared in this scope
             for (j = i ; j ; j--)
                  ^
0_0_38382865_19869.cpp:16:18: error: 'j' was not declared in this scope
             for (j = 1 ; j <= i ; j++)
                  ^