2.字符串的反转，比如abcde，输出edcba

首尾元素相交换：

#include<stdio.h>

#include<string.h>

char *change(char *a)

{
if(*a != '\0')
{
char temp;
char *s1= a;
char *s2 = a + strlen(a) - 1;

while(s1 < s2)
{
temp = *s1;
*s1 = *s2;
*s2 = temp;
*s1++;
*s2--;
}
}
return a;

}

int main(void)

{
char a[] = "abcdef";
char *b;

b = change(a);

printf("%s/n",b);

return 0;
}

递归的做法：

#include<stdio.h>

void reverse(char *a)

{
if(*a == '\0')
 return;
{
reverse(a + 1);
printf("%c",*a);
}

}

int main(void)

{
char a[] = "abdsdf";

reverse(a);

return 0;

}