View Compilation Error

0_0_18412187_8991.c: In function 'main':
0_0_18412187_8991.c:13:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(long long int i=0; i<n; ++i)
     ^
0_0_18412187_8991.c:13:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_18412187_8991.c:24:23: error: redefinition of 'i'
     for(long long int i=0; i<n; ++i)
                       ^
0_0_18412187_8991.c:13:23: note: previous definition of 'i' was here
     for(long long int i=0; i<n; ++i)
                       ^
0_0_18412187_8991.c:24:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(long long int i=0; i<n; ++i)
     ^