maybe you can, but I don't think it will make the program significantly faster... at least not to a level where you can see the difference...
but if you are really eager on making it faster, go if you are using gcc, and in the current directory, there should be a file called source.s ....
learn a bit of assembly, and you may be able to improve it
here's how it looks
Code:
.file "test.c"
.section .rodata
.LC0:
.string "%d"
.text
.globl main
.type main, @function
main:
pushl %ebp
movl %esp, %ebp
subl $24, %esp
andl $-16, %esp
movl $0, %eax
addl $15, %eax
addl $15, %eax
shrl $4, %eax
sall $4, %eax
subl %eax, %esp
subl $8, %esp
leal -12(%ebp), %eax
pushl %eax
pushl $.LC0
call scanf
addl $16, %esp
movl $0, -8(%ebp)
movl $0, -4(%ebp)
jmp .L2
.L5:
subl $12, %esp
pushl $42
call putchar
addl $16, %esp
leal -4(%ebp), %eax
incl (%eax)
.L4:
movl -12(%ebp), %eax
cmpl %eax, -4(%ebp)
jl .L5
subl $12, %esp
pushl $10
call putchar
addl $16, %esp
movl $0, -4(%ebp)
.L2:
movl -12(%ebp), %eax
cmpl %eax, -8(%ebp)
setl %dl
leal -8(%ebp), %eax
incl (%eax)
testb %dl, %dl
jne .L4
movl $0, %eax
leave
ret
.size main, .-main
.ident "GCC: (GNU) 4.0.3 20051201 (prerelease) (Debian 4.0.2-5)"
.section .note.GNU-stack,"",@progbits