实验六

Task 1

#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
    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从地址x开始的连续n个数据项中，查找特定数据项item
// 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;
}

 

 

 

 

 

 

 

 Task 2

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
void fun(char *a)
{
    int i=0;
    char *p = a;
    while (*p =='*')
    {
        a[i] = *p;
        i++;
        p++;
    }
    while (*p)
    {
        if (*p != '*')
        {
            a[i] = *p;
            i++;
        }
        p++;
    }
    a[i] = '\0';
}

int main()
{
    char s[81];
    
    printf("Enter a string :\n");
    gets(s);
    fun(s);
    printf("The string after deleted:\n");
    puts(s);

    return 0;
}

 

 

 Task 3

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void fun(char *a)
{
    int i=0;
    char *t = a, *f = a;
    char *q = a;

    while (*t)
        t++;
    t--;

    while (*t == '*')
        t--;

    while (*f == '*')
        f++;
        
    while (q < f)
    {
        a[i] = *q;
        q++;
        i++;
    }

    while (q < t)
    {
        if (*q != '*')
        {
            a[i] = *q;
            i++;
        }
        q++;
    }

    while (*q)
    {
        a[i] = *q;
        i++;
        q++;
    }
    a[i] = '\0';
}

int main()
{
    char s[81];

    printf("Entre a string:\n");
    gets(s);
    fun(s);
    printf("The sting after deleted:\n");
    puts(s);

    return 0;
}

 

 

Task 4

#include <stdio.h>
#include <string.h>

#define N 80
int isPalindrome(char *s);

int main()
{
    char str[N];
    int flag;

    printf("Enter a string:\n");
    gets(str);

    flag = isPalindrome(str);

    if (flag)
        printf("YES\n");
    else
        printf("No\n");

    return 0;
}

// 函数定义
// 功能：判断指针s指向的字符串是否是回文串，如果是，返回1；否则，返回0。
int isPalindrome(char *s)
{
	int i;
    char a[100],n=0,n0;
    char *p=s,*t=s,*r=s;
    while(*p != 0)
    {
    	p++;
    	n++;
	}
	for(i=0;i<n;i++)
		a[i]=*(t+n-1-i);
	for(i=0;i<n;i++)
		if(a[i]==*(r+i))
			return 1;
		else return 0;
}

 

 

 Task 5

 

#include <stdio.h>
#define N 80

int count(char *str, char *substr);

int main()
{
    char str[N], substr[N];
    int n;

    gets(str);      // 输入母串
    gets(substr);   // 输入子串
    n = count(str, substr);     // 函数调用
    printf("%d\n", n);

    return 0;
}

int count(char *str, char *substr)
{
    int i, j, k;
    int num = 0;

    for(i=0; str[i]!=0 ; ++i)
        for(j=i, k=0; substr[k] == str[j]; k++, j++)
            if(substr[k+1] == 0)
            {
                num++;
                break;
            }
    
    return(num);
}