88.c

来自「计算概论阅读材料」· C语言 代码 · 共 53 行

#define LINE 20
#define N 80
#include <stdio.h>
#include <string.h>
#include <alloc.h>
#include <stdlib.h>

FILE *fp;
char fname[12];
readln(char *pl[])//read filename and return total of lines
{
	int nl=0,i;
	char *p,s[80];
	while(fgets(s,80,fp)!=NULL)
		if((p=(char*)malloc(strlen(s)+1))==NULL) return -1;
	else{
		strcpy(p,s);
		pl[nl++]=p;
	}
	return nl;
}
search(char *pl[],int nl,char *str)
{
	int top=0,bottom=nl-1,mid,f;
	while(top<=bottom){
		mid=(top+bottom)/2;
		f=strcmp(str,pl[mid]);
		if(f==0)
			return mid;
		else
			if(f<0)bottom=mid-1;
			else top=mid+1;
	}
	return -1;
}
void main(void)
{
	char *pl[LINE],book[N];
	int nl,k;
	gets(fname);
	if((fp=fopen(fname,"r"))==NULL){
		printf("Can't find file \n");
		exit(1);
	}
	if((nl=readln(pl))>=0){
		gets(book);
		strcat(book,"\n");
		k=search(pl,nl,book);
		if(k!=-1) printf("%d %s\n",k,pl[k]);
		else printf("Can't find the string\n");
	}
}