根据子字符串查找删除列表条目答案

【问题标题】：Delete a list entry based on substring find根据子字符串查找删除列表条目
【发布时间】：2014-06-19 03:56:31
【问题描述】：

我想编写一个函数，如果它在结构中找到保存在作者姓名中的子字符串，则删除结构列表的条目。问题是， strstr() 似乎没有找到任何匹配项。我不想知道我是在正确删除条目还是以正确的方式移动列表指针（想自己弄清楚）。

void z(LIBRARY *first){
   int  i = 0, j = 0 ;
   LIBRARY *nextZ = first->next , *prevZ = first;
   char *name = (char*) malloc (102*sizeof(char)), *name2 = (char*) malloc (102*sizeof(char)), c ;

   getchar();

   fgets(name, 102, stdin); // Function gets the string the user is looking for.
   while (name[j]!= '\0'){
     name[j]= toupper(name[j]);  // Converts it to upper case to ignore case types.
     j++;
   }
   j=0;
   printf("%s", name);

   while ( nextZ ){ // Function starts going through the list of structures

     name2 = nextZ->authors; //Function gets string saved in current structure->authors
     while (name2[j]!= '\0'){
        name2[j]= toupper(name2[j]);
        j++;
     }
     j = 0;
     printf("%s", name2);

     if ( (strstr( name2, name))!=NULL ){ 
         /*This is where the problem is. It seems like   
         the function never finds a substring in the structure->authors entry.*/
        i++;
        prevZ->next = nextZ->next;
        nextZ = nextZ->next->next;
     }
     else {
        prevZ = prevZ->next;
        nextZ = nextZ->next;
     }

   }
 printf("Vymazalo sa %d zaznamov\n", i); //Prints out how many entries of the list got deleted.
}

【问题讨论】：

1.要了解 strstr() 是如何工作的，请编写一个简单的 main，它除了玩 strstr() 之外什么都不做。 2. 使用调试器检查每一步的所有相关变量，以了解您的程序真正执行的操作。
顺便说一句：代码在这里引入了很大的内存泄漏：name2 = nextZ->authors;
想法：把这个printf("%s", name2);改成printf("name2='%s', name='%s'\n", name2, name);
嘿，谢谢，我发现了主要问题-我将行尾字符加载到名称中，因此找不到该字符串。但是 name2 = nextZ->authors; 中的大内存泄漏是什么意思？ ?
看看你给指针name2分配了什么。

标签： c substring strstr

【解决方案1】：

我已经设法解决了我遇到的所有问题 - 这是我为任何感兴趣的人所做的：

void z(LIBRARY *first){
 int  i = 0, j = 0 ;
 LIBRARY *nextZ = first->next , *prevZ = first;
 char *name = (char*) malloc (102*sizeof(char)), *name2 = (char*) malloc (102*sizeof(char));

 getchar();  //getting an '\n' that could remain from main when calling z()

 fgets(name, 102, stdin);        //scanning author the user wants to delete
 while (name[j]!= '\0'){
     if (name[j]=='\n') {        //removing end of line character from user input
                 name[j]='\0';
                 break;
     }
     if (name[j]>='a' && name[j]<='z') name[j]= toupper(name[j]);        //chaning user choice to upper case letters for string comparison
     j++;
 }
 j=0;

 while ( nextZ ){    //While cycle that goes through the list of structures

     strcpy(name2, nextZ->authors);  //gets author name from current list entry
     while (name2[j]!= '\0'){

         if (name2[j]>='a' && name2[j]<='z') name2[j]= toupper(name2[j]);    //Once again- change to upper case for string comparison
         j++;
     }
     j = 0;

     if ( (strstr(name2,name))!=NULL ){      //strstr- returns a pointer if match is found- otherwise returns NULL
         i++;
         prevZ->next = nextZ->next; //removes the entries from the list
         nextZ = nextZ->next;

     }
     else { //if strings dont match the list moves to the next entry
         prevZ = prevZ->next; 
         nextZ = nextZ->next;
     }

 }
 printf("%d entries deleted.\n", i); //prints out number of deleted entries
}

【讨论】：