View Compilation Error

0_0_35017623_15458.c: In function 'main':
0_0_35017623_15458.c:7:12: error: 'i' undeclared (first use in this function)
        for(i=0;i<=n;++i)
            ^
0_0_35017623_15458.c:7:12: note: each undeclared identifier is reported only once for each function it appears in