86.c

计算概论阅读材料

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define LINES 10

void fastsort(char *pl[],int n)
{
	int m=1,lb[20],ub[20],low,high,i,j;
	char *t;
	lb[m]=0;ub[m]=n-1;
	while(m){
		low=lb[m];high=ub[m];m--;
		while(low<high){
			i=low;j=high;t=pl[i];
			while(i!=j){
				while(strcmp(t,pl[j])<=0&&i!=j)
					j--;
				if(i!=j){
					pl[i]=pl[j],i++;
					while(strcmp(t,pl[i])>=0&&i!=j)
						i++;
						if(i!=j)pl[j]=pl[i];
						else
							pl[i]=t;
						}
						else pl[j]=t;
					}m++;
					if(i-low<=high-i){
						ub[m]=high,lb[m]=i+1;
						high=i-1;
						}
					else{
						ub[m]=i-1;
						lb[m]=low;
						low=i+1;
					}
				}
			}
}

readln(char *pl[],int maxl)//read filename and return total of lines
{
	int nl=0,i;
	char *p,s[80];
	while(gets(s)!=NULL)
		if(nl>=maxl) return -1;
		else if((p=(char*)malloc(strlen(s)+1))==NULL) return -1;
		else{
			strcpy(p,s);
			pl[nl++]=p;
			}
	return nl;
}
void writeln(char *pl[],int nl)
{
	while(--nl>=0)
		printf("%s\n",*pl++);
}

void main(void)
{
	char *pl[LINES],*s;
	int nl,sf,sj=0;
	printf("input the strings with F6 end\n");
	if((nl=readln(pl,LINES))>=0){
		fastsort(pl,nl);
		writeln(pl,nl);
	}
	else
		printf("lines is too many");
}

/*main(int argc,char *argv[])
{
 char *pl[LINES],*s;
 int nl,sf,sj=0;
 while(--argc>0){
	s=*++argv;
	if(s[0]=='D'||s[0]=='d')
		sf=-1;
	else
		for(s=*argv;*s!='\0';s++)
			sj=10*sj+*s-48;//ASCII string to decimal
	}
	if((nl=readln(pl,LINES))>=0){
		writeln(pl,nl);
		fastsort(pl,nl,sf,sj);
		writeln(pl,nl);
	}
	else
		printf("lines is too many");
} */