foo.c:3:1: warning: missing braces around initializer [-Wmissing-braces]
foo.c:3:1: warning: (near initialization for 'f[0]') [-Wmissing-braces]
foo.c:4:1: warning: missing braces around initializer [-Wmissing-braces]
foo.c:4:1: warning: (near initialization for 'a[0]') [-Wmissing-braces]
foo.c: In function 'main':
foo.c:14:2: error: 'for' loop initial declarations are only allowed in C99 mode
foo.c:14:2: note: use option -std=c99 or -std=gnu99 to compile your code
foo.c:15:3: error: 'for' loop initial declarations are only allowed in C99 mode
foo.c:17:10: error: redefinition of 'i'
foo.c:14:10: note: previous definition of 'i' was here
foo.c:17:2: error: 'for' loop initial declarations are only allowed in C99 mode
foo.c:18:11: error: redefinition of 'j'
foo.c:15:11: note: previous definition of 'j' was here
foo.c:18:3: error: 'for' loop initial declarations are only allowed in C99 mode
foo.c:25:1: warning: control reaches end of non-void function [-Wreturn-type]