Task: Print numbers from 1 to 1000 without using any loop or conditional statements. Don’t just write the printf()
or cout
statement 1000 times.
How would you do that using C or C++?
106 Answers
This one actually compiles to assembly that doesn’t have any conditionals:
#include <stdio.h>
#include <stdlib.h>
void main(int j) {
printf("%d\n", j);
(&main + (&exit - &main)*(j/1000))(j+1);
}
Edit: Added ‘&’ so it will consider the address hence evading the pointer errors.
This version of the above in standard C, since it doesn’t rely on arithmetic on function pointers:
#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);
}