新手，求大神改错，折半查找功能运行没有实现

[yangxingwu1991]

/*

题目:
有15个数由从大到小的顺序放在一个数组中，输入一个数，
要求用折半查找法找出该数是数组中的第几个元素的值，
如果没有，则输出"无此数"。

分析:
函数调用
void paixu(int a[],int i)
void zheban(int a[],int n,int y)
int main()
*/
#include<stdio.h>
void paixu(int a[],int i)
{
int k,t,j;
for(k=0;k<14;k++)
for(i=0;i<14-k;i++)
if(a[i]<a[i+1])
{t=a[i];a[i]=a[i+1];a[i+1]=t;}
printf("排序后的数为:\n");
for(j=0;j<15;j++)
printf("%d ",a[j]);
printf("\n");
}

void zheban(int a[],int n,int y)
{
int mid ,high=14,low=0;
mid=(high+low)/2;
while(low<=high)
{
if(a[n]>y)
high=mid-1;
else if(a[n]<y)
low=mid+1;
else
printf("no");
}
printf("你要查找的是第%d个数:",n+1);
}
int main()
{
int j,b[15],z;
printf("input 15 numbers:\n");
for(j=0;j<15;j++)
{
printf("b[%d]=",j);
scanf("%d",&b[j]);
}
printf("\n");
printf("原始的序列为:\n");
for(j=0;j<15;j++)
printf("%d ",b[j]);
printf("\n");
paixu(b,j);
printf("输入一个数:");
scanf("%d",&z);
zheban(b,j,z);
return 0;
}

[赵4老师]

先
http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-cpp-express
右边Visual C++ 2010 Express下面的Select language...下拉选‘简体中文’，再按Install Now按钮


再参考C:\Program Files\Microsoft Visual Studio 10.0\VC\crt\src\bsearch.c

/***
*bsearch.c - do a binary search
*
*   Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*   defines bsearch() - do a binary search an an array
*
*******************************************************************************/

#include <cruntime.h>
#include <stdlib.h>
#include <search.h>
#include <internal.h>

#if defined (_M_CEE)
#define __fileDECL  __clrcall
#else  /* defined (_M_CEE) */
#define __fileDECL  __cdecl
#endif  /* defined (_M_CEE) */
/***
*char *bsearch() - do a binary search on an array
*
*Purpose:
*   Does a binary search of a sorted array for a key.
*
*Entry:
*   const char *key    - key to search for
*   const char *base   - base of sorted array to search
*   unsigned int num   - number of elements in array
*   unsigned int width - number of bytes per element
*   int (*compare)()   - pointer to function that compares two array
*           elements, returning neg when #1 < #2, pos when #1 > #2, and
*           0 when they are equal. Function is passed pointers to two
*           array elements.
*
*Exit:
*   if key is found:
*           returns pointer to occurrence of key in array
*   if key is not found:
*           returns NULL
*
*Exceptions:
*   Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/

#ifdef __USE_CONTEXT
#define __COMPARE(context, p1, p2) (*compare)(context, p1, p2)
#else  /* __USE_CONTEXT */
#define __COMPARE(context, p1, p2) (*compare)(p1, p2)
#endif  /* __USE_CONTEXT */

#if !defined (_M_CEE)
_CRTIMP
#endif  /* !defined (_M_CEE) */

SECURITYSAFECRITICAL_ATTRIBUTE
#ifdef __USE_CONTEXT
void * __fileDECL bsearch_s (
    REG4 const void *key,
    const void *base,
    size_t num,
    size_t width,
    int (__fileDECL *compare)(void *, const void *, const void *),
    void *context
    )
#else  /* __USE_CONTEXT */
void * __fileDECL bsearch (
    REG4 const void *key,
    const void *base,
    size_t num,
    size_t width,
    int (__fileDECL *compare)(const void *, const void *)
    )
#endif  /* __USE_CONTEXT */
{
    REG1 char *lo = (char *)base;
    REG2 char *hi = (char *)base + (num - 1) * width;
    REG3 char *mid;
    size_t half;
    int result;

    /* validation section */
    _VALIDATE_RETURN(base != NULL || num == 0, EINVAL, NULL);
    _VALIDATE_RETURN(width > 0, EINVAL, NULL);
    _VALIDATE_RETURN(compare != NULL, EINVAL, NULL);

        /*
        We allow a NULL key here because it breaks some older code and because we do not dereference
        this ourselves so we can't be sure that it's a problem for the comparison function
        */

    while (lo <= hi)
    {
        if ((half = num / 2) != 0)
        {
            mid = lo + (num & 1 ? half : (half - 1)) * width;
            if (!(result = __COMPARE(context, key, mid)))
                return(mid);
            else if (result < 0)
            {
                hi = mid - width;
                num = num & 1 ? half : half-1;
            }
            else
            {
                lo = mid + width;
                num = half;
            }
        }
        else if (num)
            return (__COMPARE(context, key, lo) ? NULL : lo);
        else
            break;
    }

    return NULL;
}

#undef __fileDECL
#undef __COMPARE

[yangxingwu1991]

经过调试，已经可以运行了。

#include<stdio.h>

void paixu(int a[],int i)
{
int k,t,j;
for(k=0;k<15;k++)
for(i=k;i<15;i++)
if(a[k]<a[i])
{
t=a[i];
a[i]=a[k];
a[k]=t;
}
printf("排序后的数为:\n");
for(j=0;j<15;j++)
printf("%d ",a[j]);
printf("\n");
}


void zheban(int a[],int y)
{
bool flag=false;
int high=14,low=0,m,mid;
for(m=0;m<15;m++)
{
mid=(high+low)/2;
if(a[mid]>y)
low=mid+1;
else if(a[mid]<y)
high=mid-1;
else
flag=true;
}
if(flag==false) printf("无此数\n");
else printf("你要查找的数是第%d个数\n",mid);

}


int main(){
int j,b[15],z;
printf("input 15 numbers:\n");
for(j=0;j<15;j++)
{
printf("b[%d]=",j);
scanf("%d",&b[j]);
}
printf("\n");
printf("原始的序列为:\n");

for(j=0;j<15;j++)
printf("%d ",b[j]);
printf("\n");
paixu(b,j);
printf("输入一个数:");
scanf("%d",&z);
zheban(b,z);
return 0;
}

[羽飞]

void paixu(int a[],int i)
{
int k,t,j;
for(k=0;k<14;k++)
for(i=0;i<14-k;i++) //这个传入的参数 i就被无情的修改了啊，有木有
if(a[i]<a[i+1])
{t=a[i];a[i]=a[i+1];a[i+1]=t;}
printf("排序后的数为:\n");
for(j=0;j<15;j++)
printf("%d ",a[j]);
printf("\n");
}

void zheban(int a[],int n,int y)
{
int mid ,high=14,low=0;
mid=(high+low)/2;
while(low<=high)
{
if(a[n]>y) //这个n到底是啥意思，我看main函数以为是数组大小，看到这里就疑惑了，请大侠指点
high=mid-1;
else if(a[n]<y)
low=mid+1;
else
printf("no");
}
printf("你要查找的是第%d个数:",n+1);
}

[ouuyang]

#include<stdio.h>
void paixu(int a[],int i)
{
	int k,t,j;
	for(k=0;k<15;k++)
		for(i=k;i<15;i++)
			if(a[k]<a[i])
			{
				t=a[i];
				a[i]=a[k];
				a[k]=t;
			}
	printf("排序后的数为:\n");
	for(j=0;j<15;j++)
		printf("%d ",a[j]);
	printf("\n");
}

void zheban(int a[],int n,int y)
{
	int mid ,high=n,low=0;
	
	while(low<high) 
	{  
		mid=(high+low)/2;
		if(a[mid]>y)  
			low=mid+1;
		else if(a[mid]<y)  
		  high=mid-1;
		else {
			printf("你要查找的是第%d个数:",mid);
			return;
		}
	}
	printf("你要查找的数不存在");
}

int main(){
	int j,b[15],z;
	printf("input 15 numbers:\n");
	for(j=0;j<15;j++)
	{
		printf("b[%d]=",j);
		scanf("%d",&b[j]);
	}
	printf("\n");
	printf("原始的序列为:\n");

	for(j=0;j<15;j++)
		printf("%d ",b[j]);
	printf("\n");

	paixu(b,j);
	
	printf("输入一个数:");
	scanf("%d",&z);
	zheban(b,j,z);
	return 0;
}