实验5

任务一

#include <stdio.h>
#define N 5
void output(int x[], int n);
int main()
{
    int x[N] = { 9, 55, 30, 27, 22 };
    int i;
    int k; 
    int t; 
    printf("original array:\n");
    output(x, N);
    k = 0;
    for (i = 1; i < N; ++i)
        if (x[i] > x[k])
            k = i;
    if (k != N - 1)
    {
        t = x[N - 1];
        x[N - 1] = x[k];
        x[k] = t;
    }
    printf("after swapped:\n");
    output(x, N);
    return 0;
}
void output(int x[], int n)
{
    int i;
    for (i = 0; i < n; ++i)
        printf("%d ", x[i]);
    printf("\n");
}

 

#include <stdio.h>
#define N 5
void output(int x[], int n);
int main()
{
    int x[N] = { 9, 55, 30, 27, 22 };
    int i;
    int t; 
    printf("original array:\n");
    output(x, N);
    for (i = 0; i < N - 1; ++i)
        if (x[i] > x[i + 1])
        {
            t = x[i];
            x[i] = x[i + 1];
            x[i + 1] = t;
        }
    printf("after swapped:\n");
    output(x, N);
    return 0;
}
void output(int x[], int n)
{
    int i;
    for (i = 0; i < n; ++i)
        printf("%d ", x[i]);
    printf("\n");
}

 task1:2次；

 task2:3次

不同：第一种找到合适值直接交换，第二种进行比较交换直到达到要求。

任务二

#include <stdio.h>
#define N 5
int binarySearch(int x[], int n, int item); 
int main() {
    int a[N] = { 2, 7, 19, 45, 66 };
    int i, index, key;
    printf("数组a中的数据:\n");
    for (i = 0; i < N; i++) printf("%d ", a[i]);
    printf("\n");
    printf("输入待查找的数据项: ");
    scanf_s("%d", &key); 
    index = binarySearch(a, 5, key);
    if (index >= 0) printf("%d 在数组中，下标为%d\n", key, index);
    else printf("%d 不在数组中\n", key);
    return 0;
}
int binarySearch(int x[], int n, int item) {
    int low, high, mid;
    low = 0;
    high = n - 1;
    while (low <= high) {
        mid = (low + high) / 2;
        if (x[mid] == item) return mid;
        else if (x[mid] > item) high = mid - 1;
        else low = mid + 1;
    }
    return -1;

 

 

 

任务三

#include <stdio.h>
#define N 5 
void selectSort(int a[], int n);
void input(int a[], int n);
void output(int a[], int n);
int main() {
    int a[N];
    printf("输入%d个整数\n", N);
    input(a, N);
    printf("排序前的数据:\n");
    output(a, N);
    selectSort(a, N); 
    printf("排序后的数据:\n");
    output(a, N);
    return 0;
}
void input(int a[], int n) {
    int i;
    for (i = 0; i < n; i++) scanf_s("%d", &a[i]);
}
void output(int a[], int n) {
    int i;
    for (i = 0; i < n; i++) printf("%d ", a[i]);
    printf("\n");
}
void selectSort(int a[], int n) {
    int i, j, k, temp;
    for (i = 0; i < n - 1; i++) {
        k = i; 
        for (j = i + 1; j < n; j++) if (a[j] < a[k]) k = j; 
        if (k != i) 
        { 
            temp = a[i];
            a[i] = a[k];
            a[k] = temp;
        }
    }
}

#include <stdio.h>
#include<string.h>
#define N 5
void selectSort(char str[][20], int n); 
int main() {
    char name[][20] = { "Bob", "Bill", "Joseph", "Taylor", "George" };
    int i;
    printf("输出初始名单:\n");
    for (i = 0; i < N; i++) printf("%s\n", name[i]);
    selectSort(name, N); 
    printf("按字典序输出名单:\n");
    for (i = 0; i < N; i++) printf("%s\n", name[i]);
    return 0;
}
void selectSort(char str[][20], int n) {
    
    char tmp[20];
    int i, j;
    for (i = 0; i < n; ++i)
        for (j = i + 1; j < n; ++j)
            if (strcmp(str[i], str[j]) == 1)
            {
                memcpy(tmp, str[i], sizeof tmp);
                memcpy(str[i], str[j], sizeof tmp);
                memcpy(str[j], tmp, sizeof tmp);
            }
    return;
}

 

任务四

#include <stdio.h>
int main() {
    int n;
    int* pn;
    n = 42;
    pn = &n;
    printf("&n = %#x, n = %d\n", &n, n);
    printf("&pn = %#x, pn = %#x\n", &pn, pn);
    printf("*pn = %d\n", *pn);
    return 0;
}

 1.0x62felc    42

 2.0x62fe10   n的地址

 3.n的地址

任务五

 

#include <stdio.h>
#define N 5
int main()
{
    int a[N] = { 1, 9, 2, 0, 7 };
    int i;
    int* p;
    for (i = 0; i < N; ++i)
        printf("&a[%d] = %#x, a[%d] = %d\n", i, &a[i], i, a[i]);
    printf("\n");
    for (i = 0; i < N; ++i)
        printf("a+%d = %#x, *(a+%d) = %d\n", i, a + i, i, *(a + i));
    printf("\n");
    p = a;
    for (i = 0; i < N; ++i)
        printf("p+%d = %#x, *(p+%d) = %d\n", i, p + i, i, *(p + i));
    return 0;
}

 1.可以

 2.可以