View Compilation Error

0_0_15263146_9925.cpp: In function 'int main()':
0_0_15263146_9925.cpp:29:9: error: 'ans' was not declared in this scope
         ans = 0
         ^
0_0_15263146_9925.cpp:30:21: error: 'i' was not declared in this scope
         for(int i=1;i<=n;i++)
                     ^
0_0_15263146_9925.cpp:35:26: error: 't1' was not declared in this scope
         printf("%.0lf\n",t1-t2);
                          ^
0_0_15263146_9925.cpp:35:29: error: 't2' was not declared in this scope
         printf("%.0lf\n",t1-t2);
                             ^