LinearSearch

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <time.h>
#include <math.h>
#define COUNT 10

int *lsearch(void* key, void* arr, size_t n, size_t size, int (*cmp)(const void*, const void*)){
    for (int i = 0; i < n * size; i += size){
        if (cmp(key, arr + i) == 0){
            return arr + i;
        }
    }
    return NULL;
}

//   *(int*)a
int compare(const void* a, const void* b){
    return *(int*)a - *(int*)b;
}

int compareD(const void* a, const void* b){
    if (fabs(a - b) < 0.001){
        return 0;
    } else if (a > b){
        return 1;
    }
    return -1;
}

struct rect {
    double w;
    double h;
};

// area
int compareRects(const void* a, const void* b){
    struct rect r1 = *(struct rect*)a;
    struct rect r2 = *(struct rect*)b;
    double area1 = r1.w * r1.h;
    double area2 = r2.w * r2.h;
    if (fabs(area1 - area2) < 0.001){
        return 0;
    } else if (area1 > area2){
        return 1;
    }
    return -1;
}

int main(){
    struct rect rectangles[10];

    srand(time(NULL));
    int nums[COUNT];
    for (int i = 0; i < COUNT; i++){
        nums[i] = rand() % 100;
    }
    //qsort(nums, COUNT, sizeof(int), compare);
    for (int i = 0; i < COUNT; i++){
        printf("%d ", nums[i]);
    }
    putchar('\n');
    int key = 20;
    int* ptr = lsearch(&key, nums, COUNT, sizeof(int), compare);
    if (ptr == NULL){
        printf("%d is not found!\n", key);
    } else {
        printf("Element %d is found!\n", key);
    }
    return 0;
}