有15个数按由大到小顺序存放在一个数组中,输入一个数,要求用折半查找法找出该数是数组中第几个元素的值。如果该数不在数组中,则输出“无此数”。
以下是此题的【c源代码】,需要【c++源代码】请点击进入
#include
#define N 15
int main()
{ int i,number,top,bott,mid,loca,a[N],flag=1,sign;
char c;
printf("enter data:\n");
scanf("%d",&a[0]);
i=1;
while(i
{scanf("%d",&a[i]);
if (a[i]>=a[i-1])
i++;
else
printf("enter this data again:\n");
}
printf("\n");
for (i=0;i
printf("%5d",a[i]);
printf("\n");
while(flag)
{printf("input number to look for:");
scanf("%d",&number);
sign=0;
top=0; //top是查找区间的起始位置
bott=N-1; //bott是查找区间的最末位置
if ((numbera[N-1])) //要查的数不在查找区间内
loca=-1; // 表示找不到
while ((!sign) && (top<=bott))
{mid=(bott+top)/2;
if (number==a[mid])
{loca=mid;
printf("Has found %d, its position is %d\n",number,loca+1);
sign=1;
}
else if (number
bott=mid-1;
else
top=mid+1;
}
if(!sign||loca==-1)
printf("cannot find %d.\n",number);;
printf("continu or not(Y/N)?");
scanf(" %c",&c);
if (c=='N'||c=='n')
flag=0;
}
return 0;
}