字符串反转

算法一：//构想交换头尾的元素，缩小头和尾

#include<stdio.h>
#define LSIZE 81

void strRev(char []);
void strRevP(char *s);
int main()
{
    char str[LSIZE]="Welcome to Beijing!";
         
    //printf("Enter string: ");
    //gets(str);
    
    printf("string is %s\n",str);
	
    strRevP(str);

    printf("\nafter reverse\n");   	
    printf("string is %s\n",str);
	
    return 0;
}

void strRev(char s[])
{
    char stemp;
    int len=0;
    int i;
	
    while (s[len]) 	//same as s[len]!='\0'
        len++;
    len--;	
    //len points to the last char in the string s;
	
    for (i=0;i<=len/2;i++)
    {
	stemp = s[i];
	s[i] = s[len-i];
	s[len-i] = stemp;
    }
}

void strRevP(char *s)
{
    char stemp;
    char *ep;	
    ep = s;
	
    while (*ep)
	ep++;
    ep--;	//end points to the last char in the string s;
	
    while (s<ep)
    {
	stemp = *s;
	*s = *ep;
	*ep = stemp;
	s++;
	ep--;
    }
}

算法二
构想：倒着构建一个新的数组已实现操作

#include<stdio.h>
#include<string.h>
#define LSIZE 81
int main()
{
	char str[LSIZE]="Welcome to Beijing!";	
	char print[LSIZE]={'0'};
	int j=strlen(str)-1;
	for(int i=0;i<strlen(str);i++)
	{
		print[j]=str[i];
		j--;
	}
	puts(print);
	return 0;
}