C:不使用循环语句或递归的循环
我想写一个C函数,它将在标准输出上每行打印1到N个,其中N是函数的int参数。函数不应使用while、for、do-while循环、goto语句、递归和switch语句。可能吗?首先将所有可能的输出写入字符串,然后在输出应该停止的地方以null终止。C:不使用循环语句或递归的循环,c,loops,C,Loops,我想写一个C函数,它将在标准输出上每行打印1到N个,其中N是函数的int参数。函数不应使用while、for、do-while循环、goto语句、递归和switch语句。可能吗?首先将所有可能的输出写入字符串,然后在输出应该停止的地方以null终止。 这是一个相当肮脏的解决方案,但考虑到局限性,我所能想到的, 当然,除了使用汇编程序之外 char a[]="1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n"/*...*/; m
这是一个相当肮脏的解决方案,但考虑到局限性,我所能想到的,
当然,除了使用汇编程序之外
char a[]="1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n"/*...*/;
main(n,v)char**v;{n=atoi(v[1]);
#define c(x)(n>x?n-x:0)
a[n+c(1)+c(9)+c(99)+c(999)+c(9999)+c(99999)+c(999999)+c(9999999)/*+...*/]=0;
puts(a);}
考虑到流行体系结构上的
MAX_INT==2147483647
,我们只需要升级到+c(999999999)
。键入初始字符串可能需要一段时间,但是…您没有禁止fork()
N是不固定的,因此无法取消循环。据我所知,C没有迭代器
你应该找到一些模仿循环的东西
或者跳出框框思考:
(例如,N限制为1000,但很容易适应)
如果你知道N的上限,你可以试试这样;)
void func(int N)
{
char*data=“1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n”;
如果(N>0&&N<12)
printf(“%s”,N*3,数据);
其他的
printf(“数据不足。需要将更多样条线网格化\n”);
}
撇开玩笑不谈,我真的不明白如果没有递归或你提到的所有指令,你怎么能做到这一点。这让我对解决方案更加好奇
编辑:刚刚注意到我提出了与格罗姆比斯特相同的解决方案:)这样做:
int main ()
{
printf ("1 to N one per each line\n");
return 0;
}
这里还有一个:
#include <stdlib.h>
#include <stdio.h>
int main (int c, char ** v) {
char b[100];
sprintf (b, "perl -e 'map {print \"$_\\n\"} (1..%s)'", v[1]);
system (b);
return 0;
}
#包括
#包括
int main(int c,字符**v){
charb[100];
sprintf(b,“perl-e'map{print\“$\\\n\”}(1..%s)”,v[1]);
系统(b);
返回0;
}
您可以使用setjmp和logjmp函数来执行此操作,如图所示
对于那些想知道为什么有人会有这样的问题的人来说,这是印度招聘应届毕业生的常见问题之一。你可以通过嵌套宏来实现这一点
int i = 1;
#define PRINT_1(N) if( i < N ) printf("%d\n", i++ );
#define PRINT_2(N) PRINT_1(N) PRINT_1(N)
#define PRINT_3(N) PRINT_2(N) PRINT_2(N)
#define PRINT_4(N) PRINT_3(N) PRINT_3(N)
:
:
#define PRINT_32(N) PRINT_31(N) PRINT_31(N)
我会选择使用
longjmp()
#包括
#包括
void do_循环(int n){
int-val;
jmp_buf env;
val=0;
setjmp(环境);
printf(“%d\n”++val);
如果(val!=n)
longjmp(env,0);
}
int main(){
杜鲁环(7);
返回0;
}
#包括
int回调(常量无效*a,常量无效*b){
静态int n=1;
如果(n带有阻塞读取、信号和报警。我认为我必须使用sigaction和SAU重启,但它似乎在没有阻塞的情况下工作得足够好
请注意,setitimer/alarm可能是特定于unix/的
#include <signal.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
volatile sig_atomic_t counter;
volatile sig_atomic_t stop;
void alarm_handler(int signal)
{
printf("%d\n", counter++);
if ( counter > stop )
{
exit(0);
}
}
int main(int argc, char **argv)
{
struct itimerval v;
v.it_value.tv_sec = 0;
v.it_value.tv_usec = 5000;
v.it_interval.tv_sec = 0;
v.it_interval.tv_usec = 5000;
int pipefds[2];
char b;
stop = 10;
counter = 1;
pipe(pipefds);
signal(SIGALRM, alarm_handler);
setitimer(ITIMER_REAL, &v, NULL);
read(pipefds[0], &b, 1);
}
#包括
#包括
#包括
#包括
#包括
易失性sig_原子计数器;
易挥发的sig_____________________________;
无效报警处理程序(int信号)
{
printf(“%d\n”,计数器++);
如果(计数器>停止)
{
出口(0);
}
}
int main(int argc,字符**argv)
{
结构itimerval v;
v、 it_value.tv_sec=0;
v、 it_value.tv_usec=5000;
v、 it_interval.tv_sec=0;
v、 it_interval.tv_usec=5000;
int-pipefds[2];
字符b;
停止=10;
计数器=1;
管道(pipefds);
信号(信号机、报警处理器);
setitimer(ITIMER_实型,&v,NULL);
读取(管道FDS[0],&b,1);
}
我很失望这不起作用。对我来说,短语“函数是在之前注册的函数之后调用的,这些函数在注册时已经被调用了”建议在开始调用atexit处理程序后可以注册它们。也就是说,一个处理程序可以注册另一个处理程序。否则,怎么可能存在一个在注册另一个函数时已被调用的函数?但对我来说,对atexit的调用返回0成功,但实际上没有重新调用又打了一个电话。有人知道为什么吗,我犯了一些愚蠢的错误吗
#include "stdio.h"
#include "stdlib.h"
int count = 0;
int limit = 10;
void handler() {
printf("%d of %d\n", ++count, limit);
if (count < limit) atexit(handler);
}
int main(int argc, char **argv) {
if (argc > 1) limit = atoi(argv[1]);
atexit(handler);
}
#包括“stdio.h”
#包括“stdlib.h”
整数计数=0;
整数极限=10;
void处理程序(){
printf(“%d,共%d\n”++计数,限制);
如果(计数<限制)atexit(处理器);
}
int main(int argc,字符**argv){
如果(argc>1)限制=atoi(argv[1]);
atexit(处理程序);
}
顺便说一句,不是递归,因为atexit不调用其参数,它将其排队等待以后调用。显然,C运行时包含一个调用atexit处理程序的循环,但无论您是否实际注册任何atexit处理程序,该循环都存在。因此,如果此程序包含一个循环,则每个C程序都会如此;-)这将从命令行获取整数N,并从1到N打印出来
#include <stdio.h>
#include <stdlib.h>
int total;
int N;
int print16(int n)
{
printf("%d\n",n+0x01); total++; if (total >= N) exit(0);
printf("%d\n",n+0x02); total++; if (total >= N) exit(0);
printf("%d\n",n+0x03); total++; if (total >= N) exit(0);
printf("%d\n",n+0x04); total++; if (total >= N) exit(0);
printf("%d\n",n+0x05); total++; if (total >= N) exit(0);
printf("%d\n",n+0x06); total++; if (total >= N) exit(0);
printf("%d\n",n+0x07); total++; if (total >= N) exit(0);
printf("%d\n",n+0x08); total++; if (total >= N) exit(0);
printf("%d\n",n+0x09); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0A); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0B); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0C); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0D); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0E); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0F); total++; if (total >= N) exit(0);
printf("%d\n",n+0x10); total++; if (total >= N) exit(0);
}
int print256(int n)
{
print16(n);
print16(n+0x10);
print16(n+0x20);
print16(n+0x30);
print16(n+0x40);
print16(n+0x50);
print16(n+0x60);
print16(n+0x70);
print16(n+0x80);
print16(n+0x90);
print16(n+0xA0);
print16(n+0xB0);
print16(n+0xC0);
print16(n+0xD0);
print16(n+0xE0);
print16(n+0xF0);
}
int print4096(int n)
{
print256(n);
print256(n+0x100);
print256(n+0x200);
print256(n+0x300);
print256(n+0x400);
print256(n+0x500);
print256(n+0x600);
print256(n+0x700);
print256(n+0x800);
print256(n+0x900);
print256(n+0xA00);
print256(n+0xB00);
print256(n+0xC00);
print256(n+0xD00);
print256(n+0xE00);
print256(n+0xF00);
}
int print65536(int n)
{
print4096(n);
print4096(n+0x1000);
print4096(n+0x2000);
print4096(n+0x3000);
print4096(n+0x4000);
print4096(n+0x5000);
print4096(n+0x6000);
print4096(n+0x7000);
print4096(n+0x8000);
print4096(n+0x9000);
print4096(n+0xA000);
print4096(n+0xB000);
print4096(n+0xC000);
print4096(n+0xD000);
print4096(n+0xE000);
print4096(n+0xF000);
}
int print1048576(int n)
{
print65536(n);
print65536(n+0x10000);
print65536(n+0x20000);
print65536(n+0x30000);
print65536(n+0x40000);
print65536(n+0x50000);
print65536(n+0x60000);
print65536(n+0x70000);
print65536(n+0x80000);
print65536(n+0x90000);
print65536(n+0xA0000);
print65536(n+0xB0000);
print65536(n+0xC0000);
print65536(n+0xD0000);
print65536(n+0xE0000);
print65536(n+0xF0000);
}
int print16777216(int n)
{
print1048576(n);
print1048576(n+0x100000);
print1048576(n+0x200000);
print1048576(n+0x300000);
print1048576(n+0x400000);
print1048576(n+0x500000);
print1048576(n+0x600000);
print1048576(n+0x700000);
print1048576(n+0x800000);
print1048576(n+0x900000);
print1048576(n+0xA00000);
print1048576(n+0xB00000);
print1048576(n+0xC00000);
print1048576(n+0xD00000);
print1048576(n+0xE00000);
print1048576(n+0xF00000);
}
int print268435456(int n)
{
print16777216(n);
print16777216(n+0x1000000);
print16777216(n+0x2000000);
print16777216(n+0x3000000);
print16777216(n+0x4000000);
print16777216(n+0x5000000);
print16777216(n+0x6000000);
print16777216(n+0x7000000);
print16777216(n+0x8000000);
print16777216(n+0x9000000);
print16777216(n+0xA000000);
print16777216(n+0xB000000);
print16777216(n+0xC000000);
print16777216(n+0xD000000);
print16777216(n+0xE000000);
print16777216(n+0xF000000);
}
int print2147483648(int n)
{
/*
* Only goes up to n+0x70000000 since we
* deal only with postive 32 bit integers
*/
print268435456(n);
print268435456(n+0x10000000);
print268435456(n+0x20000000);
print268435456(n+0x30000000);
print268435456(n+0x40000000);
print268435456(n+0x50000000);
print268435456(n+0x60000000);
print268435456(n+0x70000000);
}
int main(int argc, char *argv[])
{
int i;
if (argc > 1) {
N = strtol(argv[1], NULL, 0);
}
if (N >=1) {
printf("listing 1 to %d\n",N);
print2147483648(0);
}
else {
printf("Must enter a postive integer N\n");
}
}
#包括
#包括
整数合计;
int N;
int print16(int n)
{
printf(“%d\n”,n+0x01);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x02);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x03);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x04);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x05);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x06);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x07);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x08);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x09);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x0A);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x0B);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x0C);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x0D);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x0E);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x0F);总计++;如果(总计>=n)退出(0);
printf(“%d\n”,n+0x10);总计++;如果(总计>=n)退出(0);
}
int print256(int n)
{
第16(n)条;
print16(n+0x10);
print16(n+0x20);
print16(n+0x30);
print16(n+0x40);
print16(n+0x50);
print16(n+0x60);
print16(n+0x70);
print16(n+0x80);
print16(n+0x90);
print16(n+0xA0);
print16(n+0xB0);
打印16(n+0xC0);
print16(n+0xD0);
print16(n+0xE0);
print16(n+0xF0);
}
int print4096(int n)
{
打印256(n);
打印256(n+0x100);
#include <stdio.h>
#include <setjmp.h>
void do_loop(int n) {
int val;
jmp_buf env;
val = 0;
setjmp(env);
printf("%d\n", ++val);
if (val != n)
longjmp(env, 0);
}
int main() {
do_loop(7);
return 0;
}
#include <stdlib.h>
int callback(const void *a, const void *b) {
static int n = 1;
if (n <= N)
printf("%d\n", n++);
return 0;
}
int main(int argc, char *argv) {
char *buf;
/* get N value here */
buf = malloc(N); // could be less than N, but N is definitely sufficient
qsort(buf, N, 1, callback);
}
#include <signal.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
volatile sig_atomic_t counter;
volatile sig_atomic_t stop;
void alarm_handler(int signal)
{
printf("%d\n", counter++);
if ( counter > stop )
{
exit(0);
}
}
int main(int argc, char **argv)
{
struct itimerval v;
v.it_value.tv_sec = 0;
v.it_value.tv_usec = 5000;
v.it_interval.tv_sec = 0;
v.it_interval.tv_usec = 5000;
int pipefds[2];
char b;
stop = 10;
counter = 1;
pipe(pipefds);
signal(SIGALRM, alarm_handler);
setitimer(ITIMER_REAL, &v, NULL);
read(pipefds[0], &b, 1);
}
#include "stdio.h"
#include "stdlib.h"
int count = 0;
int limit = 10;
void handler() {
printf("%d of %d\n", ++count, limit);
if (count < limit) atexit(handler);
}
int main(int argc, char **argv) {
if (argc > 1) limit = atoi(argv[1]);
atexit(handler);
}
#include <stdio.h>
#include <stdlib.h>
int total;
int N;
int print16(int n)
{
printf("%d\n",n+0x01); total++; if (total >= N) exit(0);
printf("%d\n",n+0x02); total++; if (total >= N) exit(0);
printf("%d\n",n+0x03); total++; if (total >= N) exit(0);
printf("%d\n",n+0x04); total++; if (total >= N) exit(0);
printf("%d\n",n+0x05); total++; if (total >= N) exit(0);
printf("%d\n",n+0x06); total++; if (total >= N) exit(0);
printf("%d\n",n+0x07); total++; if (total >= N) exit(0);
printf("%d\n",n+0x08); total++; if (total >= N) exit(0);
printf("%d\n",n+0x09); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0A); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0B); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0C); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0D); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0E); total++; if (total >= N) exit(0);
printf("%d\n",n+0x0F); total++; if (total >= N) exit(0);
printf("%d\n",n+0x10); total++; if (total >= N) exit(0);
}
int print256(int n)
{
print16(n);
print16(n+0x10);
print16(n+0x20);
print16(n+0x30);
print16(n+0x40);
print16(n+0x50);
print16(n+0x60);
print16(n+0x70);
print16(n+0x80);
print16(n+0x90);
print16(n+0xA0);
print16(n+0xB0);
print16(n+0xC0);
print16(n+0xD0);
print16(n+0xE0);
print16(n+0xF0);
}
int print4096(int n)
{
print256(n);
print256(n+0x100);
print256(n+0x200);
print256(n+0x300);
print256(n+0x400);
print256(n+0x500);
print256(n+0x600);
print256(n+0x700);
print256(n+0x800);
print256(n+0x900);
print256(n+0xA00);
print256(n+0xB00);
print256(n+0xC00);
print256(n+0xD00);
print256(n+0xE00);
print256(n+0xF00);
}
int print65536(int n)
{
print4096(n);
print4096(n+0x1000);
print4096(n+0x2000);
print4096(n+0x3000);
print4096(n+0x4000);
print4096(n+0x5000);
print4096(n+0x6000);
print4096(n+0x7000);
print4096(n+0x8000);
print4096(n+0x9000);
print4096(n+0xA000);
print4096(n+0xB000);
print4096(n+0xC000);
print4096(n+0xD000);
print4096(n+0xE000);
print4096(n+0xF000);
}
int print1048576(int n)
{
print65536(n);
print65536(n+0x10000);
print65536(n+0x20000);
print65536(n+0x30000);
print65536(n+0x40000);
print65536(n+0x50000);
print65536(n+0x60000);
print65536(n+0x70000);
print65536(n+0x80000);
print65536(n+0x90000);
print65536(n+0xA0000);
print65536(n+0xB0000);
print65536(n+0xC0000);
print65536(n+0xD0000);
print65536(n+0xE0000);
print65536(n+0xF0000);
}
int print16777216(int n)
{
print1048576(n);
print1048576(n+0x100000);
print1048576(n+0x200000);
print1048576(n+0x300000);
print1048576(n+0x400000);
print1048576(n+0x500000);
print1048576(n+0x600000);
print1048576(n+0x700000);
print1048576(n+0x800000);
print1048576(n+0x900000);
print1048576(n+0xA00000);
print1048576(n+0xB00000);
print1048576(n+0xC00000);
print1048576(n+0xD00000);
print1048576(n+0xE00000);
print1048576(n+0xF00000);
}
int print268435456(int n)
{
print16777216(n);
print16777216(n+0x1000000);
print16777216(n+0x2000000);
print16777216(n+0x3000000);
print16777216(n+0x4000000);
print16777216(n+0x5000000);
print16777216(n+0x6000000);
print16777216(n+0x7000000);
print16777216(n+0x8000000);
print16777216(n+0x9000000);
print16777216(n+0xA000000);
print16777216(n+0xB000000);
print16777216(n+0xC000000);
print16777216(n+0xD000000);
print16777216(n+0xE000000);
print16777216(n+0xF000000);
}
int print2147483648(int n)
{
/*
* Only goes up to n+0x70000000 since we
* deal only with postive 32 bit integers
*/
print268435456(n);
print268435456(n+0x10000000);
print268435456(n+0x20000000);
print268435456(n+0x30000000);
print268435456(n+0x40000000);
print268435456(n+0x50000000);
print268435456(n+0x60000000);
print268435456(n+0x70000000);
}
int main(int argc, char *argv[])
{
int i;
if (argc > 1) {
N = strtol(argv[1], NULL, 0);
}
if (N >=1) {
printf("listing 1 to %d\n",N);
print2147483648(0);
}
else {
printf("Must enter a postive integer N\n");
}
}
int main() {
return system("seq 7");
}
/// <summary>
/// Print one to Hundred without using any loop/condition.
/// </summary>
int count = 100;
public void PrintOneToHundred()
{
try
{
int[] hey = new int[count];
Console.WriteLine(hey.Length);
count--;
PrintOneToHundred();
}
catch
{
Console.WriteLine("Done Printing");
}
}
int x=1;
void PRINT_2(int);
void PRINT_1(int n)
{ if(x>n)
return;
printf("%d\n",x++);
PRINT_2(n);
}
void PRINT_2(int n)
{ if(x>n)
return;
printf("%d\n",x++);
PRINT_1(n);
}
int main()
{ int n;
scanf("%d",&n);
if(n>0)
PRINT_1(n);
system("pause");
}
#include "stdio.h"
#include "stdlib.h"
#include "signal.h"
int g_num;
int iterator;
void signal_print()
{
if(iterator>g_num-1)
exit(0);
printf("%d\n",++iterator);
}
void myprintf(int n)
{
g_num=n;
int *p=NULL;
int x= *(p); // the instruction is reexecuted after handling the signal
}
int main()
{
signal(SIGSEGV,signal_print);
int n;
scanf("%d",&n);
myprintf(n);
return 0;
}