实验二

#include<stdio.h>

int main() {
    long n = 0, high = 0, low = 0, change = 0;
    int flag1 = 0, flag2 = 0; //flag for odd/even number

    scanf("%lx",&n);
    printf("n: %#lx\n",n); //输入一个长整型数字

    high = (n>>16) & 0x0000ffff; //move high 16 bits to low
    low = n & 0x0000ffff;
    flag1 = (high%2)? 1: 0;
    flag2 = (low%2)? 1: 0;
    printf("0为偶数，1为奇数\n") ;
    printf("high: %#lx ------%d\nlow: %#lx------%d\n",high,flag1,low,flag2);
    //判断高十六位和第十六位的奇偶

    change = ((n&0x00ff0000)>>8) + ((n&0x0000ff00)<<8) + ((n&0x000000ff)<<24) + ((n&0xff000000)>>24) ;
    printf("after change: %#lx\n",change) ;

    return 0 ;
}

实验四

#include <stdio.h>

int main(void) {
    int input_no = 0;
    int split[4] = {10};
    int i = 0;
    int order[4] = {10};
    int tmp = 0;

    printf("enter a number between 1000 and 9999: ");

    scanf("%d", &input_no);

    while(input_no<1000||input_no>9999) {
        printf("invalid input, enter your number again:");
        scanf("%d", &input_no);
    } //不在范围内的时候报错

    while(input_no) {
        split[i] = input_no % 10;
        input_no /= 10;
        i++;
    } //将该数字拆分成位，存在数组里

    printf("reverse number is: ");
    for(int i=0; i<4; i++) {
        printf("%d", split[i]);
    } //反序打印数组里的数字

    printf("\n");

    for(int m=1; m<4; m++) {
        for(int n=0; n<4-m; n++) {
            if(split[n]>split[n+1])
            {
                tmp = split[n];
                split[n] = split[n+1];
                split[n+1] = tmp;
            }
        }
    } //冒泡排序，降序

    printf("the smallest number can produce is: ");
    for(int f=0; f<4; f++) {
        printf("%d", split[f]);
    }//打印排序后的数组，从大到小，从而构建“最大数字”

    printf("\n");

    printf("the largest number can produce is: ");
    for(int p=3; p>=0; p--) {
        printf("%d", split[p]);
    }//反序打印，构建最小数字

    printf("\n");

    return 0;
}

实验六

#include <stdio.h>

void bubble_sort(int arr[], int total);
void selection_sort(int a[], int total);
void Merge(int a[], int b[], int sorted[], int alen, int blen);


int main(void){
    int arr_1[10] = {0};
    int arr_2[10] = {0};
    int tmp1 = 0, tmp2 = 0;
    int sorted[20] = {0};
    int max = 0;

    printf("enter first array: \n");
    for(int i=0; i<10; i++){
        scanf("%d ", &arr_1[i]);
    }
    printf("enter another array: \n");
    for(int i=0; i<10; i++){
        scanf("%d ", &arr_2[i]);
    }

    bubble_sort(arr_1, 10);
    selection_sort(arr_2, 10);
    Merge(arr_1, arr_2, sorted, 10, 10);

    for(int j=0; j<20; j++){
        printf("%d ", &sorted[j]);
    }

    return 0;
}

void bubble_sort(int arr[], int total){
    int tmp = 0;
    for(int i=0; i<total-1; i++){
        for(int j=0; j<total-1-i; j++){
            if(arr[j+1]<arr[j]){
                tmp = arr[j+1];
                arr[j+1] = arr[j];
                arr[j] = tmp;
            }
        }
    }
}

void selection_sort(int a[], int total){
    int max_index = 0, tmp = 0;
    for(int i=0; i<total-1; i++){
        max_index = i;
        for(int j=i+1; j<total; j++){
            if(a[max_index]>a[j]) max_index = j;

            tmp = a[max_index];
            a[max_index] = a[i];
            a[i] = tmp; //when ends a line, exchage between a[max] and **a[i]**
        }
    }
}

void Merge(int a[], int b[], int sorted[], int alen, int blen){
    int i = 0, j = 0;
    while(i<alen && j<blen){
        sorted[i+j] = a[i]>b[j]? a[i++] : b[j++];
    }

    while(i<alen){
        sorted[i+j] = a[i++];
    }

    while(j<blen){
        sorted[i+j] = b[j++];
    }
}

实验八

#include <stdio.h>

bool Like[5][5] = {
    {0, 0, 1, 1, 0},
    {1, 1, 0, 0, 1},
    {0, 1, 1, 0, 1},
    {0, 0, 0, 1, 0},
    {0, 1, 0, 0, 1}
};
int book[5] = {0}; //0 for not attr
int n = 0;

void Try(int i);

int main(void){
   Try(0);
   return 0;
}

void Try(int i){
    int j = 0, k = 0;
    for(j=0; j<5; j++){
        if(Like[i][j]&& book[j]==0){
            book[j] = i + 1; //give book_j to ith person
            if(i==4){
                n++;
                printf("方案%d:\n", n);
                for(k=0; k<5; k++){
                    printf("第%d本书分给%c\n", k, (char)(book[k]-1+'A'));
                }
                printf("\n");
            }
            else
                Try(i + 1);
            book[j] = 0;
        }
    }
}

实验十

#include <stdio.h>
#include <string.h>
/*
 * 默认6786xxxx-->
 * 结束时间hour:min:sec
 */

int TeleAttr(char *no);

int main(void) {
    int loc = 4;
    float pr = 0.000;

    struct Time {
        int hour;
        int min;
        int second;
    };

    struct Tele_Info {
        struct Time ymd; //year month date
        char call_no[50]; // 主叫码
        char called_no[50]; //被叫码
        struct Time start_time; //通话开始时间
        struct Time time_len; //通话时长
        float price; //话单价格
    }; //declaration of struct



    struct Tele_Info p[6]; //declaration of struct array
    struct Tele_Info tele;
    struct Tele_Info tmp;

    for(int i=0; i<6; i++) {
        scanf("%d-%d-%d ", &tele.ymd.hour, &tele.ymd.min, &tele.ymd.second);
        scanf("%s %s", tele.call_no, tele.called_no); //ymd

        scanf("%d:%d:%d", &tele.start_time.hour, &tele.start_time.min, &tele.start_time.second);
        scanf("%d:%d:%d", &tele.time_len.hour, &tele.time_len.min, &tele.time_len.second);

        pr = 0;

        loc = TeleAttr(tele.called_no);
        switch(loc){
            case 0: pr = tele.time_len.hour * 6 + (tele.time_len.min - 3 + 1) * 0.1 + 3 * 0.2; break;
            case 1: pr = tele.time_len.hour * 36 + (tele.time_len.min + 1) * 0.6; break;
            case 2: pr = tele.time_len.hour * 60 + tele.time_len.min + 1; break;
        }
        tele.price = pr;
        p[i] = tele;
    } //assign and cal price

    for(int m=1; m<6; m++) {
        for(int n=0; n<6-m; n++) {
            if(p[n].price<p[n+1].price)
            {
                tmp = p[n];
                p[n] = p[n+1];
                p[n+1] = tmp;
            }
        }
    } //bubble sort, high->low

    printf("排序后： ");
    printf("\n");
    for(int s=0; s<6; s++) {
        tele = p[s];
        printf("%d", s+1);
        printf(" %d-%d-%d", tele.ymd.hour, tele.ymd.min, tele.ymd.second);
        printf(" %s %s", tele.call_no, tele.called_no);
        printf(" %d:%d:%d", tele.start_time.hour, tele.start_time.min, tele.start_time.second);
        printf(" %d:%d:%d", tele.time_len.hour, tele.time_len.min, tele.time_len.second);
        printf("\n");
    }

    return 0;
}

int TeleAttr(char *called_no) {
    int lena = strlen(called_no);
    if(called_no[0]=='\0') return 1; //domestic
    if(lena==8) return 0; //city
    else return 2; //foreign
} //default 6786xxxx ->