View Compilation Error

0_0_35041261_4827.c: In function 'main':
0_0_35041261_4827.c:7:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for(int i=0;i<n;i++)
  ^
0_0_35041261_4827.c:7:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_35041261_4827.c:10:10: error: redefinition of 'i'
  for(int i=1;i<=a[k];i++)
          ^
0_0_35041261_4827.c:7:10: note: previous definition of 'i' was here
  for(int i=0;i<n;i++)
          ^
0_0_35041261_4827.c:10:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for(int i=1;i<=a[k];i++)
  ^
0_0_35041261_4827.c:12:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(int j=0;j<a[k];j++)
   ^