//z 不用循环和条件判断打印1-1000
//z 2011-05-24 19:16:07@is2120
#include
<iostream>
template
<int
N>
struct
NumberGeneration{
static
void
out(std::ostream& os)
{
NumberGeneration<N-1
>::out(os);
os << N << std::endl;
}
};
template
<>
struct
NumberGeneration<1
>{
static
void
out(std::ostream& os)
{
os << 1
<< std::endl;
}
};
int
main(){
NumberGeneration<1000
>::out(std::cout);
}
/*
————————————————————————————————————————————
*/
/*
@PP, that's quite lengthy to explain, but basically, j is initially 1 because
it's actually argc, which is 1 if the program is called without arguments. Then,
j/1000 is 0 until j becomes 1000, after which it's 1. (exit - main) is, of
course, the difference between the addresses of exit() and main(). That means
(main + (exit - main)*(j/1000)) is main() until j becomes 1000, after which it
becomes exit(). The end result is that main() is called when the program starts,
then calls itself recursively 999 times while incrementing j, then calls exit().
Whew :)
*/
#include
<stdio.h>
#include
<stdlib.h>
void
main(int
j) {
printf("
%d
/n
"
, j);
(&main + (&exit - &main)*(j/1000
))(j+1
);
}
#include
<stdio.h>
#include
<stdlib.h>
void
f(int
j)
{
static
void
(*const
ft[2
])(int
) = { f, exit };
printf("
%d
/n
"
, j);
ft[j/1000
](j + 1
);
}
int
main(int
argc, char
*argv[])
{
f(1
);
}
/*
————————————————————————————————————————————
*/
/*
I'm surprised nobody seems to have posted this -- I thought it was the most
obvious way. 1000 = 5*5*5*8.
*/
#include
<stdio.h>
int
i = 0
;
p() { printf("
%d
/n
"
, ++i); }
a() { p();p();p();p();p(); }
b() { a();a();a();a();a(); }
c() { b();b();b();b();b(); }
main() { c();c();c();c();c();c();c();c(); return
0
; }
/*
————————————————————————————————————————————
*/
[ Edit: (1
) and
(4
) can be used for
compile time constants only, (2
) and
(3
) can
be used for
runtime expressions too — end edit. ]
// compile time recursion
template
<int
N> void
f1()
{
f1<N-1
>();
cout << N << '/n'
;
}
template
<> void
f1<1
>()
{
cout << 1
<< '/n'
;
}
// short circuiting (not a conditional statement)
void
f2(int
N)
{
N && (f2(N-1
), cout << N << '/n'
);
}
// constructors!
struct
A {
A() {
static
int
N = 1
;
cout << N++ << '/n'
;
}
};
int
main()
{
f1<1000
>();
f2(1000
);
delete
[] new
A[1000
]; // (3)
A data[1000
]; // (4) added by Martin York
}
/*
————————————————————————————————————————————
*/
#include
<stdio.h>
#define MAX
1000
int
boom;
int
foo(n) {
boom = 1
/ (MAX-n+1
);
printf("
%d
/n
"
, n);
foo(n+1
);
}
int
main() {
foo(1
);
}
//z 2011-05-24 19:16:11@is2120