View Compilation Error

0_0_24821704_8853.cpp: In function 'void set_table()':
0_0_24821704_8853.cpp:9:10: error: 'i' was not declared in this scope
     for (i=1;i<21;i++)
          ^
0_0_24821704_8853.cpp: In function 'int main()':
0_0_24821704_8853.cpp:17:10: error: 'i' was not declared in this scope
      for(i=0;i<21;i++)
          ^
0_0_24821704_8853.cpp:25:9: error: 'i' was not declared in this scope
     for(i=t;i<=n;i++)
         ^