字符串练习——删除子串的n中方法

1、

#include <stdio.h>
#include <string.h>

int  delete(char *str,char *str_son,char *result_str)
{
int i = 0;
int str_son_len = strlen(str_son);
int str_len = strlen(str);
int count = 0;

if(strcmp(str,str_son) == 0)                              //两者相等，返回空；
    {
        result_str = NULL;
        printf("error!\n");
return 0;
    }

if(str_len < str_son_len || str_son == NULL)              //子串大于主串，或子串为空，输出主串
    {
while(*str != '\0')
        {
            *result_str = *str;
str++;
            result_str++;
        }
return 0;
    }

while(*str != '\0')
    {
while((*str != *str_son)&&( *str_son != '\0'))         //两者不相等
        {
            *result_str = *str;
str ++;
            result_str ++;
        }
if(strncmp(str,str_son,str_son_len) != 0)
        {
            *result_str = *str;
str ++;
            result_str ++;
        }
else
        {
count ++;
str += str_son_len;
        }

    }

    *result_str = '\0';

return count;
}

int main()
{
char str[100];
char t[20];
char s[100];

    printf("please input str:\n");
    scanf("%s",str);
    printf("please input son:\n");
    scanf("%s",t);

    delete(str,t,s);

    printf("the result is :%s\n",s);

return 0;
}

---

2、

#include<string.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
char a[20];
char *p=a;
char *q;
char *temp=(char*)malloc(sizeof(char)*20);
int len;

printf("please a:\n");
scanf("%s",a);
printf("please temp:\n");
scanf("%s",temp);

    len = strlen(temp);

while((q = strstr(p,temp)) != NULL)                
    {
strcpy(q,q+len);                      
     }

puts(p);

free(temp);

return 0;

}

---

3、

/*
 src = "wangwangana" -> dest = "an" -> "wagwg"
*/

#include <stdio.h>
#include <stdlib.h>

static int delete(char *src,char *dest,char *result)
{
/* judge paramter */
if(src == NULL || dest == NULL)
    {
return -1;
    }
char *ptr = src;    ////main string
char *str = dest;   ////sub string
int count = 0;
int i = 0;
int flag;

while(*ptr != '\0')
    {
        count = 0;   //////统计子串 和主串 相同的个数
    flag = 0;    ////判断子串和主串是否存在第一个字符相同
while(*str != '\0' && *ptr == *str)
    {
        flag = 1;
        ptr++;
        str++;
            count++;
    }
/* flag == 1 时，说明执行了上面的子串和主串*/
if(flag == 1)
    {
if(*str == '\0')
        {
            str = dest;  ///将子串str反回到原来dest
continue;
        }
else
       {
           str = dest;
/* 将和主串不完全相同的子串部分 赋值给result*/
           ptr = ptr - count;
for(i = 0; i < count;i++)
           {
               *result = *ptr;
           ptr++;
           result++;
           }
continue;
       }
    }
/* 主串 和 子串 不一样的情况下 赋值给result*/
    *result = *ptr;
        ptr++;
    result++;
    }
    *result = '\0';
return 0;
}

int main()
{
char *src;
char *dest;
char *result;

     src = (char *)malloc(100*sizeof(char));
     dest = (char *)malloc(100*sizeof(char));
     result = (char *)malloc(100*sizeof(char));

printf("please input src string:\n");
scanf("%s",src);
printf("please input dest string:\n");
scanf("%s",dest);

delete(src,dest,result);
printf("result = %s\n",result);

free(src);
     src = NULL;
free(dest);
     dest = NULL;
free(result);
     result = NULL;
return 0;
}