数组元素查找的通用写法举例

叁歲伎倆 2022-08-21 09:42 156阅读 0赞

*  在一个整形数组中查找元素

#include <stdio.h>
    #include <string.h>
    
    void *lSearch(void* key, void* base, int n, int elemSize);
    
    int main()
    {
        int array[] = {
       4,3,5,7,9,8};
        int elemNum = 6;
        int key = 70;
        void *result = lSearch(&key, array, elemNum, sizeof(int));
        if (result != NULL) {
            printf("Get the item !\n");
        } else { printf("Not get yet !\n"); }
    
        return 0;
    }
    
    /* The function for item compareation */
    int StrCmp(void *vp1, void *vp2)
    {
        char *s1 = *(char**)vp1;
        char *s2 = *(char**)vp2;
    
        return strcmp(s1, s2);
    }
    
    /* The input is an integer array key: 待查找的关键字内存存储位置 base: 待查找集合的内存存储位置 base: 待查找集合中的元素个数 elemSize: 待查找集合中每个元素的大小字节数 */
    void *lSearch(void* key, void* base, int n, int elemSize)
    {
        int i;
        for (i=0; i<n; i++)
        {
            void *elemAddr = (char*)base + i*elemSize;
            if (memcmp(key, elemAddr, elemSize) == 0) { 
                return elemAddr;
            }
        }
        return NULL;
    }

--------------------

*  在一个字符指针数组中查找某一个字符串是否存在

#include <stdio.h>
    #include <string.h>
    
    int StrCmp(void *vp1, void *vp2);
    void *StrSearch(void* key, void* base, int n, int elemSize, int (*cmp)(void*, void*));
    
    
    
    int main()
    {
        char *strArr[] = {
       "Ab", "B#", "CS", "D", "EF"};
        char *key = "Ab";
        if (StrSearch(&key, strArr, 5, sizeof(char*), StrCmp))                   {
          printf("Get the item !\n");
    } else { printf("Not get the item !\n"); }
    
        return 0;
    }
    
    /* The function for item compareation */
    int StrCmp(void *vp1, void *vp2)
    {
        char *s1 = *(char**)vp1;
        char *s2 = *(char**)vp2;
    
        return strcmp(s1, s2);
    }
    /* The input is an array which contains char* type items */
    void *StrSearch(void* key, void* base, int n, int elemSize, int (*cmp)(void*, void*))
    {
        int i;
        for (i=0; i<n; i++)
        {
            void *elemAdrr = (char*)base + i*elemSize;
            if (cmp(key, elemAdrr) == 0) {
                return elemAdrr;
            }
        }
        return NULL;
    }