prog.c: In function ‘main’:
prog.c:6:1: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘p’
p = 0
^
prog.c:6:1: error: ‘p’ undeclared (first use in this function)
prog.c:6:1: note: each undeclared identifier is reported only once for each function it appears in
prog.c:7:1: error: expected ‘;’ before ‘p’
p = p + 1
^