#include<stdio.h>
#include<stdlib.h>
int strTime(const char *str1, const char *str2, int *time)
{int count = 0;char *p1 = str1;char *p2 = str2;//p1是第一次出现的位置p1 = strstr(p1, p2);//注意这里不要写成*p1!=NULL 由于p1 是null的地址一旦读取*p1 会出错的!!!!不能读取操作系统的数据//千万不要写成 *p//while (*p1 != '\0')//while (p1 != NULL)while (p1){count++;//让指针向后移动str2长度个位置p1 = p1+strlen(str2);//找到下一次出现的位置p1 = strstr(p1, p2);}*time = count;return 1;
}
//这里也能够实现出现次数的查询/*int strTime(const char *str1, const char *str2, int *time)
{char *p = NULL;int count = 0;char *sub = NULL;p = str1;sub = str2;do{p = strstr(p, sub);if (p != NULL){count++;p = p + strlen(sub);}else{break;}} while (*p != '\0');*time = count;
}*/int getRes2(const char *str, const char *substr, int *time, char **buf2){char *buf = (char *)malloc(strlen(str)*sizeof(char));char *pbuf = buf;//进行字符串的替换char *p = NULL;char *sub = NULL;p = str;sub = substr;int flag = 4;//仅仅要是不相等的情况下就将字符复制到buf中char *point = "dcba";while (*p != '\0'){if (*p != *sub){*buf = *p;buf++;p++;//printf("%s\n", pbuf);}//想等情况下也就是找到了须要替换的位置else{for (int i = 0; i < flag; i++){*buf = *point;buf++;point++;// printf("%s\n", pbuf);}//控制4321循环flag--;//这里须要将离开了"dcba"首地址的指针又一次定位回去point = "dcba";if (flag == 0){flag = 4;}//相等的时候须要让p指针跨越四个字节也就是他下一次进行查找的位置p += 4;}}//对末尾的加上字符串结束标志防止输出时乱码*buf = '\0';//二级指针的典型使用方法*buf2 = pbuf;
}
void main()
{char *str1 = "abcd11111abcd2222abcdqqqqqabcd11111abcd2222abcdqqqqqabcd11111abcd2222abcdqqqqq";char *str2 = "abcd";int time = 0;//1求字符串"abcd"出现的次数strTime(str1, str2, &time);printf("出现的次数是%d\n", time);char *buf = NULL;//把字符串替换成(dcba11111dcb2222dqqqqqdd11111dcba.....)//注意特点逆序后,每次字符少一个,四次一循环;getRes2(str1, str2, &time, &buf);printf("原来的字符串   %s\n", str1);printf("替换后的字符串 %s\n", buf);system("pause");
}