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

1.2

#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]);
}

2

#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==1)
     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;
}

3

#include <stdio.h>
const int 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,max;
    max=x[0];
    for(i=1;i<=n;i++)
    if(max<x[i]){
        max=x[i];
    }
    returm max;
}

#include <stdio.h>
void dec2n(int x, int n); 
int main()
{
  int x;
  printf("輸入一個十進位制整數: ");
  scanf("%d", &x);
  dec2n(x, 2);  
  dec2n(x, 8); 
  dec2n(x, 16); 
  return 0;
}
// 函式定義
// 功能: 把十進位制數x轉換成n進位制，列印輸出
// 補足函式實現
void dec2n(int x, int n){
    int a[100],i,b;
    b=x;i=1;
    if(n==2){
        while(x!=0){
        a[i++]=x%2;
        x=x/2;
        }
        for(i=i-1;i>0;i--)
        printf("%d",a[i]);
        printf("\n");
    }
    if(n==8){
        while(x!=0){
        a[i++]=x%8;x=x/8;
        }
        for(i=i-1;i>0;i--)
        printf("%d",a[i]);
        printf("\n");
    }
    if(n==16){
        while(x!=0){
        a[i++]=x%16;x=x/16;
        }
        for(i=i-1;i>0;i--){
            if(a[i]<10)
                printf("%d",a[i]);
            if(a[i]>=10)
            switch(a[i]){
                case 10:printf("%c",'A');break;
                case 11:printf("%c",'B');break;
                case 12:printf("%c",'C');break;
                case 13:printf("%c",'D');break;
                case 14:printf("%c",'E');break;
                case 15:printf("%c",'F');break;
            }
        }
    
        printf("\n");
    }
    
}