实验五

#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;    // 用于记录最大元素的下标
  int t;    // 用作交换两个数组元素的中间变量
  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");
} 

 

 

#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);
// 调用函数binarySearch()在数组a中查找指定数据项key,并返回查找结果给index
// 补足代码①
 index=binarySearch(a,N,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;
}
//函数功能描述：
//使用二分查找算法在数组x中查找特定值item，数组x大小为n
// 如果找到，返回其下标
// 如果没找到，返回-1
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 (item==x[mid])
return mid;
else if (item<x[mid])
high = mid - 1;
else
low = mid + 1;
}
return -1;
} 

 

 

 

#include <stdio.h>
#include<string.h>
#define N 5
void selectSort(char str[][20], int n); // 函数声明，两维数组作为函数参数
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); // 调用选择法对name数组中的字符串排序
printf("按字典序输出名单:\n");
for (i = 0; i < N; i++)
printf("%s\n", name[i]);
return 0;
}
// 函数定义
// 函数功能描述：使用选择法对二维数组str中的n个字符串按字典序排序
void selectSort(char str[][20], int n)
{
  int i,j,k;
    char t[20];
    for (i = 0; i < n; i++)
    {
        k = i;
        
        for (j = i + 1; j < n; j++)
            if (strcmp(str[j], str[k]) < 0)
                k = j;
        
        if (k != i){
            strcpy(t, str[i]);
            strcpy(str[i], str[k]);
            strcpy(str[k], t);
        }
    }
}

 

#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;
}

 

#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;
}