编写程序实现对输入的字符串排序(可以规定比较的字符)

2016-03-08 来源：eefocus

一. 程序功能

编写程序实现对输入的字符串排序, 如果主函数传递了-n参数, 则按数字排序,否则按字符串排序.

同时,如果传递了-r参数,则降序, 否则升序.

同时,如果传递了-f参数,则不区分大小写

同时,如果传递了-d参数,则仅仅对alpha字符排序.

同时,如果参数中有+2 -10,则仅仅比较第2个字符到第10个字符

二. 程序源码

//main.c

#include

#define NUMERIC 1

#define DECR 2

#define FOLD 4

#define DIR 8

#define MAXLINES 5000

#define MAXLEN 1000

#define MAXSTORAGE 10000

char *lineptr[MAXLINES];

char lines[MAXSTORAGE];

int charcmp(char *, char *);

void error(char *);

int numcmp(char *, char *);

void readargs(int argc, char *argv[]);

int p_readlines(char *lineptr[], int maxlines);

void p_qsort(void *v[], int left, int right, int (*comp)(void *, void *));

void writelines(char *lineptr[], int nlines, int order);

char option = 0;

int pos1 = 0;

int pos2 = 0;

int main(int argc, char *argv[])

{

int nlines;

int rc = 0;

readargs(argc, argv);

if ((nlines = p_readlines(lineptr, MAXLINES)) > 0) {

if (option & NUMERIC)

p_qsort((void **)lineptr, 0, nlines-1, (int (*)(void *, void *))numcmp);

else

p_qsort((void **)lineptr, 0, nlines-1, (int (*)(void *, void *))charcmp);

writelines(lineptr, nlines, option & DECR);

} else {

printf("input too big to sort!\n");

rc = -1;

}

system("pause");

return rc;

}

void readargs(int argc, char *argv[])

{

int c;

while (--argc > 0 && (c = (*++argv)[0]) == '-' || c == '+') {

if (c == '-' && !isdigit(*(argv[0]+1)))

{

while (c = *++argv[0])

{

switch(c) {

case 'd':

option |= DIR;

break;

case 'f':

option |= FOLD;

break;

case 'n':

option |= NUMERIC;

break;

case 'r':

option |= DECR;

break;

default:

printf("sort: illegal option %c\n", c);

error("Usage: sort -dfnr [+pos1] [-pos2]");

break;

}

} else if (c == '-') {

pos2 = atoi(argv[0]+1);

} else if ((pos1 = atoi(argv[0]+1)) < 0)

error("Usage: sort -dfnr [+pos1] [-pos2]");

}

if (argc || pos1 > pos2)

error("Usage: sort -dfnr [+pos1] [-pos2]");

}

int p_readlines(char *lineptr[], int maxlines)

{

int len, nlines;

char *p = lines, line[MAXLEN];

nlines = 0;

printf("Please input a string(# to end input): ");

while ((len = getline(line, MAXLEN)) > 0)

{

if (strcmp(line, "#\n") == 0)

break;

if (nlines >= maxlines || p + len >= lines + MAXSTORAGE)

return -1;

else {

line[len - 1] = '\0';

strcpy(p, line);

lineptr[nlines++] = p;

p += len;

}

printf("Please input a string(# to end input): ");

}

return nlines;

}

void writelines(char *lineptr[], int nlines, int order)

{

int i;

if (order)

for (i = nlines -1; i >= 0; i--)

printf("%s\n", lineptr[i]);

else

for (i = 0; i < nlines; i++)

printf("%s\n", lineptr[i]);

printf("\n");

}

void swap(void *v[], int i, int j)

{

void *temp;

temp = v[i];

v[i] = v[j];

v[j] = temp;

}

int getline(char s[], int lim)

{

int c, i;

for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)

s[i] = c;

if (c == '\n')

{

s[i] = c;

++i;

}

s[i] = '\0';

return i;

}

void p_qsort(void *v[], int left, int right, int(*comp)(void *, void *))

{

int i, last;

if (left >= right)

return;

swap(v, left, (left + right) / 2);

last = left;

for (i = left + 1; i <= right; i++)

{

if ((*comp)(v[i], v[left]) < 0)

swap(v, ++last, i);

}

swap(v, left, last);

p_qsort(v, left, last - 1, comp);

p_qsort(v, last + 1, right, comp);

}

void error(char *s)

{

printf("%s\n", s);

exit(1);

}

//numcmp.c

#include

#define MAXSTR 100

void substr(char *s, char *t, int maxstr);

int numcmp(char *s1, char *s2)

{

double v1, v2;

char str[MAXSTR];

substr(s1, str, MAXSTR);

v1 = atof(str);

substr(s2, str, MAXSTR);

v2 = atof(str);

if (v1 < v2)

return -1;

else if (v1 > v2)

return 1;

else

return 0;

}

#define FOLD 4

#define DIR 8

int charcmp(char *s, char *t)

{

char a, b;

int i, j, endpos;

extern char option;

extern int pos1, pos2;

int fold = (option & FOLD) ? 1: 0;

int dir = (option & DIR) ? 1: 0;

i = j = pos1;

if (pos2 > 0)

endpos = pos2;

else if ((endpos = strlen(s)) > strlen(t))

endpos = strlen(t);

do {

if (dir) {

while (i < endpos && !isalpha(s[i]) && s[i] != ' ' && s[i] != '\0')

i++;

while (j < endpos && !isalpha(t[j]) && t[j] != ' ' && t[j] != '\0')

j++;

}

if (i < endpos && j < endpos) {

a = fold ? tolower(s[i]): s[i];

i++;

b = fold ? tolower(t[j]): t[j];

j++;

if (a == b && a == '\0')

return 0;

}

} while (a == b && i < endpos && j < endpos);

return a - b;

}

//substr.c

#include

void error(char *);

void substr(char *s, char *str)

{

int i, j, len;

extern int pos1, pos2;

len = strlen(s);

if (pos2 > 0 && len > pos2)

len = pos2;

else if (pos2 > 0 && len < pos2)

error("substr: string too short");

for (j = 0, i = pos1; i < len; i++, j++)

str[j] = s[i];

str[j] = '\0';

}

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