函数名: lsearch 
 功  能: 线性搜索 
 用  法: #include <stdlib.h>
         void *lsearch(const void *key, void *base, size_t *nelem, 
         size_t width, int (*fcmp)(const void *, const void *)); 
 程序例: 
#include <stdio.h> 
 #include <stdlib.h> 
int compare(int *x, int *y) 
 { 
    return( *x - *y ); 
 } 
int main(void) 
 { 
    int array[5] = {35, 87, 46, 99, 12}; 
    size_t nelem = 5; 
    int key; 
    int *result; 
   key = 99; 
    result = lfind(&key, array, &nelem, 
                sizeof(int), (int(*)(const void *,const void *))compare); 
    if (result) 
       printf("Number %d found\n",key); 
    else 
       printf("Number %d not found\n",key); 
   return 0; 
 }