实验四

1.

#include <stdio.h>
#define N 4
#define M 2

void test1() 
{
    int x[N] = {1, 9, 8, 4};          
    int i;

    printf("sizeof(x) = %d\n", sizeof(x));

    for (i = 0; i < N; ++i)
        printf("%p: %d\n", &x[i], x[i]);

    printf("x = %p\n", x); 
}

void test2() 
{
    int x[M][N] = {{1, 9, 8, 4}, {2, 0, 4, 9}};
    int i, j;

    printf("sizeof(x) = %d\n", sizeof(x));

    for (i = 0; i < M; ++i)
        for (j = 0; j < N; ++j)
            printf("%p: %d\n", &x[i][j], x[i][j]);
    printf("\n");

    printf("x = %p\n", x);
    printf("x[0] = %p\n", x[0]);
    printf("x[1] = %p\n", x[1]);
    printf("\n");
}

int main() 
{
    printf("测试1: int型一维数组\n");
    test1();

    printf("\n测试2: int型二维数组\n");
    test2();

    return 0;
}

1.是；是

2.是；是；差16字节，意义是该数组每行占用16字节数

2

#include <stdio.h>
#define N 100

void input(int x[], int n);
double compute(int x[], int n);

int main() 
{
    int x[N];
    int n, i;
    double ans;

    while(printf("Enter n: "), scanf("%d", &n) != EOF) 
    {
        input(x, n);           
        ans = compute(x, n);   
        printf("ans = %.2f\n\n", ans);
    }

    return 0;
}

void input(int x[], int n) 
{
    int i;

    for(i = 0; i < n; ++i)
        scanf("%d", &x[i]);
}

double compute(int x[], int n) 
{
    int i, high, low;
    double ans;

    high = low = x[0];
    ans = 0;

    for(i = 0; i < n; ++i) 
    {
        ans += x[i];

        if(x[i] > high)
            high = x[i];
        else if(x[i] < low)
            low = x[i];
    }

    ans = (ans - high - low)/(n-2);

    return ans;
}

1.input：将输入n值放入数组x

 compute：计算数组除最大最小数之后的平均值

3

#include <stdio.h>
#define N 100

void output(int x[][N], int n);
void init(int x[][N], int n, int value);

int main() 
{
    int x[N][N];
    int n, value;

    while(printf("Enter n and value: "), scanf("%d%d", &n, &value) != EOF) 
    {
        init(x, n, value);  
        output(x, n);       
        printf("\n");
    }

    return 0;
}

void output(int x[][N], int n) 
{
    int i, j;

    for(i = 0; i < n; ++i) {
        for(j = 0; j < n; ++j)
            printf("%d ", x[i][j]);
        printf("\n");
    }
}

void init(int x[][N], int n, int value) 
{
    int i, j;

    for(i = 0; i < n; ++i)
        for(j = 0; j < n; ++j)
            x[i][j] = value;
}

1.第二维大小不能省略

2.output：输出数组的元素

 init：将数组的元素赋值为value

4

#include <stdio.h>
#define N 100

void input(int a[],int n);
double median(int a[],int n);

int main() 
{
    int x[N];
    int n;
    double ans;

    while(printf("Enter n: "), scanf("%d", &n) != EOF) 
    {
        input(x, n);
        ans = median(x, n);
        printf("ans = %g\n\n", ans);
    }

    return 0;
}
void input(int a[],int n)
{
    int i; 
    for(i=0;i<n;i++)
    {
        scanf("%d",&a[i]);
    }
}
double median(int a[],int n)
{
    int i,j;
    for(i=0;i<n-1;i++)
    {
        for(j=0;j<n-i-1;j++)
        {
            if(a[j]>a[j+1])
            {
                int temp=a[j];
                a[j]=a[j+1];
                a[j+1]=temp;
            }
        }
    }
    if(n%2==1)
    {
        return (double)a[n/2];
    }
    else
    {
        return ((double)a[n/2-1]+(double)a[n/2])/2;
    }
    return 0;
}

5

#include <stdio.h>
#define N 100

void input(int x[][N], int n);
void output(int x[][N], int n);
void rotate_to_right(int x[][N], int n);

int main() 
{
    int x[N][N];
    int n;

    printf("输入n: "); 
    scanf("%d", &n);
    input(x, n);

    printf("原始矩阵:\n");
    output(x, n);

    rotate_to_right(x, n);

    printf("变换后矩阵:\n");
    output(x, n);

    return 0;
}


void input(int x[][N], int n) 
{
    int i,j;
    
    for (i = 0; i < n; ++i) 
    {
        for (j = 0; j < n; ++j)
            scanf("%d", &x[i][j]);
    }
}


void output(int x[][N], int n) 
{
    int i,j;

    for (i = 0; i < n; ++i) 
    {
        for (j = 0; j < n; ++j)
            printf("%4d", x[i][j]);

        printf("\n");
    }
}

void rotate_to_right(int x[][N], int n) 
{
    int temp[N][N];
    int i,j,o,p,k;
    for(k=0;k<n;++k)
    {
        temp[k][0]=x[k][n-1];
    }
    for(j=1;j<n;++j)
    {
        for(i=0;i<n;++i)
        {
            temp[i][j]=x[i][j-1];
        }
    }   
    for( o=0;o<n;++o)
    {
        for( p=0;p<n;++p)
        {
            x[p][o]=temp[p][o];
        }
    }
}

6

#include <stdio.h>
#define N 100

void dec_to_n(int x, int n); 

int main() 
{
    int x;

    while(printf("输入十进制整数: "), scanf("%d", &x) != EOF) 
    {
        dec_to_n(x, 2);
        printf("\n");  
        dec_to_n(x, 8); 
        printf("\n");   
        dec_to_n(x, 16); 
        printf("\n");
    }

    return 0;
}

void dec_to_n(int x, int n)
{
    int s[N];
    int t=0;
    if(x==0)
    {
        printf("0");
        return;
    }
    
    while(x)
    {
        s[t++]=x%n;
        x/=n;
    }
    while(t>0)
    {
        int d=s[--t];
        if(d<10)
        {
            printf("%d",d);
        }
        else
        {
            printf("%c",d-10+'A');
        }
    }
}