实验五

//task1
#include <stdio.h>
#define N 5

void output(int x[], int n);

int main()
{
    int x[] = {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");          
          
      }

 

//task1.2
#include <stdio.h>
#define N 5

void output(int x[], int n);

int main()
{
    int x[] = {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");          
          
      }

 

//task 2
#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("%d",&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;
    
}

 

 

 

//task 3
#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("%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;//k用于记录当前最小元素的下标
        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;
        }
    }
}

 

//task 4
#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("输入初始名单:\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)
{
    int i, j;
    char temp[20];
    for(i = 0;i<n - 1;i++)
    {
    
        for(j = i+1;j<n;j++)
        {
            if(strcmp(str[j],str[i])<0)
            {
                strcpy(temp,str[j]);
                strcpy(str[j],str[i]);
                strcpy(str[i],temp);  
            } 
         }  
    }
}

 

//task 5
#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;
}

 

//task 6
#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;
    
 }