这里有个二分查找例子可供参考,使用了自定义函数可以实现你的题目要求:
#include <stdio.h>
binarySearch(int a[], int n, int key){
int low = 0;
int high = n - 1;
while(low<= high){
int mid = (low + high)/2;
int midVal = a[mid];
if(midVal<key)
low = mid + 1;
else if(midVal>key)
high = mid - 1;
else
return mid;
}
return -1;
}
int main(){
int i, val, ret;
int a[8]={-32, 12, 16, 24, 36, 45, 59, 98};
for(i=0; i<8; i++)
printf("%d\t", a[i]);
printf("\n请输人所要查找的元素:");
scanf("%d",&val);
ret = binarySearch(a,8,val);
if(-1 == ret)
printf("查找失败 \n");
else
printf ("查找成功 \n");
return 0;
}
冒泡排序:
# include <stdio.h>
int main(void)
{
int a[] = {900, 2, 3, -58, 34, 76, 32, 43, 56, -70, 35, -234, 532, 543, 2500};
int n; //存放数组a中元素的个数
int i; //比较的轮数
int j; //每轮比较的次数
int buf; //交换数据时用于存放中间数据
n = sizeof(a) / sizeof(a[0]); /*a[0]是int型, 占4字节, 所以总的字节数除以4等于元素的个数*/
for (i=0; i<n-1; ++i) //比较n-1轮
{
for (j=0; j<n-1-i; ++j) //每轮比较n-1-i次,
{
if (a[j] < a[j+1])
{
buf = a[j];
a[j] = a[j+1];
a[j+1] = buf;
}
}
}
for (i=0; i<n; ++i)
{
printf("%d\x20", a[i]);
}
printf("\n");
return 0;
}
c++数组排序,二分查找,有没有规定用什么方法排序呢
冒泡排序:
#include "stdio.h"
void main()
{
int a[10]={10,8,7,20,30,9,1,50,100,-1};
int i,j,t,k;
printf("排序之前:\n");
for(i=0;i<10;i++)
printf("%d\t",a[i]);
printf("\n");
for(i=0;i<10;i++)
{
printf("i=%d,第%d轮:\n",i,i+1);
for(j=i+1;j<=9;j++)
{
if(a[i]>a[j])
{
t=a[i]; //t是临时变量
a[i]=a[j];
a[j]=t;
}
//打印排序过程:
printf("j=%d\t",j);
for(k=0;k<10;k++)
printf("%d\t",a[k]);
printf("\n");
//---------------
}
}
printf("排序之后:\n");
for(i=0;i<10;i++)
printf("%d\t",a[i]);
printf("\n");
}
二分查找
#include "stdio.h"
void main()
{
int a[15]={15,14,13,12,11,10,9,8,7,6,5,4,3,2,1};
int left,right,mid;
int num,cnt=0;
printf("请输入你要查找的数据:");
scanf("%d",&num);
left = 0;
right= 14;
while(left<=right){
//计算查找次数
cnt++;
//获取中间位置元素的下标
mid = (left+right)/2;
if(num<a[mid]){
//往右找
left=mid+1;
}else if(num>a[mid]){
//往左找
right=mid-1;
}else{
//找到了
printf("在第%d个位置找到了数据,共查找%d次\n",mid+1,cnt);
break;
}
};
if(left>right){
printf("你要查找的数据不存在\n");
}
}
先进行冒泡排序,二分查找就是从排好序的数组的中间开始查找,根据大小再向左右再找对半的中间值比较,直到结束或找到为止
合并后的代码:
# include <stdio.h>
binarySearch(int a[], int n, int key){
int low = 0;
int high = n - 1;
while(low<= high){
int mid = (low + high)/2;
int midVal = a[mid];
if(midVal<key)
low = mid + 1;
else if(midVal>key)
high = mid - 1;
else
return mid;
}
return -1;
}
int main(void)
{
int val, ret;
int a[] = {900, 2, 3, -58, 34, 76, 32, 43, 56, -70, 35, -234, 532, 543, 2500};
int n; //存放数组a中元素的个数
int i; //比较的轮数
int j; //每轮比较的次数
int buf; //交换数据时用于存放中间数据
n = sizeof(a) / sizeof(a[0]); /*a[0]是int型, 占4字节, 所以总的字节数除以4等于元素的个数*/
printf("排序前的数组为:\n");
for (i=0; i<n; ++i)
{
printf("%d\x20", a[i]);
}
printf("\n\n");
for (i=0; i<n-1; ++i) //比较n-1轮
{
for (j=0; j<n-1-i; ++j) //每轮比较n-1-i次,
{
if (a[j] > a[j+1])
{
buf = a[j];
a[j] = a[j+1];
a[j+1] = buf;
}
}
}
printf("排序后的数组为:\n\n");
for (i=0; i<n; ++i)
{
printf("%d\x20", a[i]);
}
printf("\n\n请输入要查找的数:");
scanf("%d",&val);
ret = binarySearch(a,20,val);
if(-1 == ret)
printf("查找失败,按任意键退出 \n");
else
printf ("查找成功 \n");
}
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