使用递归函数的字符串反向程序 [英] string reverse program using recursive function

问题描述

在此程序中，我没有得到输出，也没有发现我的错误，只有指出我的错误并仅给我提示，那里的任何其他方法仅给我提示. ..

In this program i did''t get output i did''t find out my mistake any one point-out my mistake and give me a hint only and any other method ''s there give the hint to me only...

#include<stdio.h>
#include<conio.h>

void fun(char *s, int l1);
void main()
{
//void rev(char, int);
char str;
int l;
clrscr();

printf("Enter the string: ");
scanf("%s",&str);
printf("%s",str);
//s=&str;
l = strlen(str);
fun(&str,l);
getch();
}

void fun(char *s,int l1)
{
 char *temp;

 if(l1 == -1)
 exit(0);

 else
  {
    temp = s+(l1-1);
    printf("%c",*temp);
    l1-=1;
    fun(s,l1);
  }

}

推荐答案

立即跳出来的一件事是，您正在使用的不是您自己的内存！

也就是说，您的变量"str"是一个char-它仅保留1个字节的内存，但是在scanf语句中，您正在将未知数量的char读入您拥有的一个字节的内存中((未知)字符数-1)存储到随后的内存中.

您应该:

• 静态或动态分配一些内存
• 使用

The thing that immediately leaps out at one is the fact that you''re using memory that isn''t yours!

That is to say, your variable ''str'' is a char - it holds just 1 byte of memory, yet in the scanf statement you''re reading an unknown number of chars into just one byte of memory you own and (unknown number of chars - 1) into memory that follows.

You should:

• Allocate some memory, either statically or dynamically
• use scanf_s[^], which allows you to specify the max # of chars copied

const int bufSize = 1024;
char str[bufSize];  // or some other arbitrary num long enough to hold string

或

const int bufSize = 1024;
char *str;
str = (char*)calloc(bufSize, 1);   // see above note on length - alloc & clear mem

然后使用:

And then use:

scanf_s("%s", str, bufSize-1);

我没有看过程序的其余部分.这可能会或可能不会解决您的问题.无论如何，仍然是您应该解决的错误.

I haven''t looked at the rest of the program. This may or may not fix your problem. In any case, it''s still an error that you should fix.

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