View Compilation Error

0_0_8011384_20945.cpp: In function `int main()':
0_0_8011384_20945.cpp:8: error: `s' undeclared (first use this function)
0_0_8011384_20945.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8011384_20945.cpp:9: error: `i' undeclared (first use this function)