8-15.cpp

能判断二次函数是否有根

/*3208006411*/
#include<stdio.h>
#include<string.h>
#define N 10
void main()
{void input(int[],char name[][8]);
void sort(int[],char name[][8]);
void search(int ,int [],char name[][8]);
int num[N],number,flag=1,c;
char name[N][8];
input(num,name);
sort(num,name);
while(flag==1)
{printf("\ninput number to look for:");
scanf("%d",&number);
search(number,num,name);
printf("continue or not(Y/N)?");
getchar();
c=getchar();
if(c=='N'||c=='n')
 flag=0;}}
void input(int num[],char name[N][8])
{int i;
for(i=0;i<N;i++)
{printf("\ninput No. :");
scanf("%d",&num[i]);
printf("input name:");
getchar();
gets(name[i]);
}}
void sort(int num[],char name[N][8])
{int i,j,min,temp1;
char temp2[8];
for(i=0;i<N-1;i++)
  {min=i;
   for(j=i+1;j<N;j++)
     if(num[min]>num[j])  min=j;
     temp1=num[i];
     strcpy(temp2,name[i]);
     num[i]=num[min];
     strcpy(name[i],temp2);
     num[min]=temp1;
     strcpy(name[min],temp2);}
  printf("\n result :\n");
  for(i=0;i<N;i++)
     printf("\n %5d%10s",num[i],name[i]);
     }
void search(int n,int num[],char name[N][8])
{int top,bott,mid,loca,sign;
top=0;
bott=N-1;
loca=0;
sign=1;
if((n<num[0])||(n>num[N-1]))
loca=-1;
while((sign==1)&&(top<=bott))
 {mid=(bott+top)/2;
 if(n==num[mid])
   {loca=mid;
   printf("No. %d,his name is%s.\n",n,name[loca]);
   sign=-1;
   }
else if(n<num[mid])
 bott=mid-1;
 else
   top=mid+1;
   }
if(sign==1||loca==-1)
  printf("can not find%d.\n",n);
  }