C语言-搜索

#include 
#include 

//查找
int search(int key, int a[], int length);
//数组作为函数参数时，往往要用另一个参数传入数组的大小
//不能直接在[]写出数组长度，也不能用sizeof()

int main(void)
{
    int a[] ={2,4,6,5,1,3,5,9,11,13,23,14,32};//数组的集成初始化
    //int a[13] ={0};
    int x;
    int loc;
    printf("请输入一个数字:");
    scanf("%d",&x);
    loc=search(x,a,sizeof(a)/sizeof(a[0]));//整个数组占据的单元/单个数组元素占据的单元=数组的单元个数
    if (loc != -1)
    {
        printf("%d在第%d个位置上n",x,loc);
    }
    else{
        printf("%d不存在n",x);
    }

    return 0;
}

int search(int key, int a[], int length)
{
    int ret = -1;
    int i;
    for(i=0;i 
查找钱数对应的英文表达 
线性搜索-遍历 
#include 
#include 

//线性搜索：遍历
//割裂的结构对cache是不友好的

int search(int key, int a[], int len)
{
    int ret = -1;
    for(int i=0;i-1)
    {
        printf("%sn",name[r]);
    }

    return 0;
}
 
 struct 
#include 
#include 

struct{
    int amount;
    char *name;
}coins[] = {
    {1,"penny"},
    {5,"nickel"},
    {10,"dime"},
    {25,"quarter"},
    {50,"half-dollar"},
};

int main()
{
    int k=25;
    for(int i=0;i 
二分搜索 
#include 
#include 

//二分搜索
int search(int key,int a[],int len)
{
    int ret = -1;
    int left=0;
    int right=len-1;
    while(right>=left)
    {
        int mid=(left+right)/2;
        if(a[mid] == key){
            ret=mid;
            break;
        }else if(a[mid] > key)
        {
            right=mid-1;
        }else
        {
            left=mid+1;
        }
    }
    return ret;
}

int main()
{
    int k=55;
    int a[] = {1,2,35,55,56,63,64,67,78,90};
    int c= search(k,a,sizeof(a)/sizeof(a[0]));
    printf("%d",c);

    return 0;
}