实验4

task1_1.cpp

#include<stdio.h> 
const int N = 4;
int main() {
    int a[N] = {2,0,2,1};
    char b[N] = {'2','0','2','1'};
    int i;
    printf("sizeof(int) = %d\n", sizeof(int));
    printf("sizeof(char) = %d\n", sizeof(char));
    printf("\n");
    for (i = 0; i < N; ++i)
        printf("%x: %d\n", &a[i], a[i]);
    printf("\n");
    for (i = 0; i < N; ++i)
        printf("%x: %c\n", &b[i], b[i]);
    return 0;
}

 

① int型数组a，在内存中是连续存放的 每个元素占用4个内存字节单元

② char型数组b，在内存中是连续存放的 每个元素占用1个内存字节单元

task1_2.cpp

 

#include<stdio.h> 
int main() {
    int a[2][3] = {{1,2,3},{4,5,6}};
    char b[2][3] = {{'1','2','3'},{'4','5','6'}};
    int i,j;
    for (i = 0; i < 2; ++i) 
       for (j = 0; j < 3; ++j)
            printf("%x: %d\n", &a[i][j], a[i][j]);    
    printf("\n");    
   for (i = 0; i < 2; ++i) 
        for (j = 0; j < 3; ++j)
            printf("%x: %c\n", &b[i][j], b[i][j]);
    return 0;
}

 

task2.cpp

 

#include<stdio.h> 
#define N 1000 
int fun(int n, int m, int bb[N])
{
    int i, j, k = 0, flag;
    for (j = n; j <= m; j++) {
        flag = 1;
        for (i = 2; i < j; i++)
            if (j % i == 0)
            {
                flag = 0;
                break;
            }
        if (flag != 0)
            bb[k++] = j;
    }
    return k;
}
int main() {
    int n = 0, m = 0, i, k, bb[N];
    scanf("%d", &n);
    scanf("%d", &m);
    for (i = 0; i < m - n; i++)
        bb[i] = 0;
    k = fun(n, m, bb);
    for (i = 0; i < k; i++)
        printf("%4d", bb[i]);
    return 0;
}

 

 

 

 

task3.cpp

#include <stdio.h> 
#define N 5
int find_max(int x[], int n); 
void input(int x[], int n); 
void output(int x[], int n);
int main() {
    int a[N]; 
    int max;
    input(a, N); 
    output(a, N); 
    max = find_max(a, N);
    printf("max = %d\n", max); 
    return 0;
}
void input(int x[], int n) {
    int i;
    for (i = 0; i < n; ++i)
        scanf("%d", &x[i]);
}
void output(int x[], int n) {
    int i;
    for (i = 0; i < n; ++i) 
        printf("%d ", x[i]); 
    printf("\n");
}
int find_max(int x[], int n) {
    int i, j, k;
    for (i = 0; i < n; i++) {
        for (j = i + 1; j < n; j++) {
            if (x[i] > x[j])
                k = x[i];
            else
                k = x[j];
        }
    }
    return k;        
}

 

 

task4.cpp

 

#include <stdio.h> 
void dec2n(int x, int n);
int main() {
    int x;
    printf("输入一个十进制整数: ");
    scanf("%d", &x);
    dec2n(x, 2);
    dec2n(x, 8);
    dec2n(x, 16);
    return 0;
}
void dec2n(int x, int n) {
    int i = 0,j, c;
    int a[32];
    if (n == 2){
        
        while (x!=0) {
            c = (x % n);
            a[i] = c;
            x = x / n;
            i++;
        }
        for(i--;i>=0;i--)
          printf("%d", a[i]);
        printf("\n");
        }
    if (n == 8)
        printf("%o\n", x);
    if (n == 16)
        printf("%x\n", x);
}

 

task5.cpp

#include<stdio.h> 
#define N 20
#define M 20
int a[N][M];
int main() {
    int j, i, n;
    n = 1;
    for (i = 0; i < N; i++) {
        for (j = 0; j < M; j++) {
            if (i < j)
                a[i][j] = i + 1;
            else
                a[i][j] = j + 1;
        }
    }
    scanf("%d", &n);
        for (i = 0; i < n; i++) {
            for (j = 0; j < n; j++)
                printf("%d ", a[i][j]);
            printf("\n");
        } 
    return 0;
}