如何提取所有号码的开出一个字符串在C只能用sscanf的格式如下:
" (3, 2, 4,5, 10 )"
空格可以无处不在,但当然不是数字之间。有可能在每个位置上0空白字符以上。
该字符串必须有正确的格式或它的错误。 “(3,2”,例如是一个错误。每一个字,这不是一个空格或格式的一部分是错误的
只使用sscanf的(其不可选)
我的想法,当然,是在与sscanf的循环,但格式是我的问题
编辑:一些括号内的金额可以是不同的。因此,我们可以有0号或N号的括号内。 n是任意数量。 (A,A + 1,...,A + N)。
EDIT2:当然是允许的使用包含在stdio.h一切,但没有扩展库
看来,数据的格式可以概括为:白色空间的任何地方;开括号随后通过逗号分隔和终止由右括号的一个或多个普通整数(没有迹象,没有小数点)的序列。另外,有可能是(
和)
之间的零个整数。
的数据必须使用sscanf()
进行处理;有关于一个调用sscanf()
没有既定规则。对使用sscanf()
在文件I / O的替代品(scanf()
,fscanf()
等)的优点是,你可以在必要时重试扫描。
需要注意的是scanf()
家人不处理“可选项”非常好。白色空间主要是微不足道的 - 除了%c
,%[…]
(扫描套),所有的转换说明%n
跳过前导空格,并在格式字符串中空格字符输入匹配零个或多个空格。
该功能string_analyzer()
做工作;它有一个适度复杂的接口,因为它不进行I / O本身 - 它分析该字符串,并增加了编号,以传递到函数的阵列结构。它还设置了一个消息,告知呼叫者一些关于什么地方出了错。其它功能是支持功能(用于struct int_array
类型)和测试工具(main()
加test_string_analyzer()
)。
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct int_array
{
char *base;
size_t maxlen;
size_t curlen;
};
static void dump_int_array(const char *tag, const struct int_array *array);
static void add_to_int_array(struct int_array *array, int data);
static void free_int_array(struct int_array *array);
static void test_string_analyzer(const char *str);
static int string_analyzer(const char *str, struct int_array *array, char **msg)
{
int offset;
int length = strlen(str);
int data;
char trailer;
if (sscanf(str, " ( %[)] %n", &trailer, &offset) == 1)
{
/* Empty list */
assert(trailer == ')');
if (offset == length)
{
*msg = "it is an empty list";
return 0;
}
else
{
*msg = "it has extra characters after an empty list";
return -1;
}
}
if (sscanf(str, " ( %d %c%n", &data, &trailer, &offset) != 2 ||
(trailer != ',' && trailer != ')'))
{
*msg = "it does not start correctly";
return -1;
}
add_to_int_array(array, data);
if (trailer == ')' && offset == length)
{
*msg = "it is valid";
return 0;
}
const char *source = str + offset;
while (sscanf(source, "%d %[,)] %n", &data, &trailer, &offset) == 2)
{
add_to_int_array(array, data);
length = strlen(source);
if (trailer == ')' && offset == length)
{
*msg = "it is valid";
return 0;
}
else if (trailer == ')')
{
*msg = "it does not end correctly";
return -1;
}
source += offset;
}
*msg = "it is incorrectly formatted";
return -1;
}
int main(void)
{
const char *samples[] =
{
/* Valid */
" (3, 2, 4,5, 10 )",
" ( 4 , 6 ) ",
"(4)",
"()",
/* random -n 15 10 99 | commalist -t -B 8 -b '"( ' -T ' )",' */
"( 65, 83, 81, 60, 61, 23, 48, 89, 67, 27, 73, 25, 92, 13, 67 )",
/* Invalid */
" (3,2, ",
"3,2",
" (3,2,1) apathy",
" () apathy",
" (3,X,1)",
" (3X,1)",
};
enum { NUM_SAMPLES = sizeof(samples) / sizeof(samples[0]) };
for (int i = 0; i < NUM_SAMPLES; i++)
test_string_analyzer(samples[i]);
return 0;
}
static void test_string_analyzer(const char *str)
{
struct int_array array = { 0, 0, 0 };
char *msg = 0;
printf("Analyzing [%s]\n", str);
int rc = string_analyzer(str, &array, &msg);
if (rc == 0)
printf("String '%s' OK: %s\n", str, msg);
else
printf("String '%s' is misformatted: %s\n", str, msg);
dump_int_array("List contents", &array);
free_int_array(&array);
}
static void dump_int_array(const char *tag, const struct int_array *array)
{
int length = printf("%s (%zu): ", tag, array->curlen);
const char *pad = "";
for (size_t i = 0; i < array->curlen; i++)
{
length += printf("%s%d", pad, array->base[i]);
pad = ", ";
if (length >= 64)
{
pad = " ";
length = 0;
putchar('\n');
}
}
if (length > 0)
putchar('\n');
}
static void add_to_int_array(struct int_array *array, int data)
{
if (array->curlen >= array->maxlen)
{
assert(array->curlen == array->maxlen);
size_t newlen = array->maxlen * 2 + 2;
void *newarr = realloc(array->base, newlen * sizeof(array->base[0]));
if (newarr == NULL)
{
}
array->base = newarr;
array->maxlen = newlen;
}
array->base[array->curlen++] = data;
}
static void free_int_array(struct int_array *array)
{
free(array->base);
array->base = 0;
array->maxlen = 0;
array->curlen = 0;
}
输出示例:
Analyzing [ (3, 2, 4,5, 10 )]
String ' (3, 2, 4,5, 10 )' OK: it is valid
List contents (5): 3, 2, 4, 5, 10
Analyzing [ ( 4 , 6 ) ]
String ' ( 4 , 6 ) ' OK: it is valid
List contents (2): 4, 6
Analyzing [(4)]
String '(4)' OK: it is valid
List contents (1): 4
Analyzing [()]
String '()' OK: it is an empty list
List contents (0):
Analyzing [( 65, 83, 81, 60, 61, 23, 48, 89, 67, 27, 73, 25, 92, 13, 67 )]
String '( 65, 83, 81, 60, 61, 23, 48, 89, 67, 27, 73, 25, 92, 13, 67 )' OK: it is valid
List contents (15): 65, 83, 81, 60, 61, 23, 48, 89, 67, 27, 73, 25
92, 13, 67
Analyzing [ (3,2, ]
String ' (3,2, ' is misformatted: it is incorrectly formatted
List contents (2): 3, 2
Analyzing [3,2]
String '3,2' is misformatted: it does not start correctly
List contents (0):
Analyzing [ (3,2,1) apathy]
String ' (3,2,1) apathy' is misformatted: it does not end correctly
List contents (3): 3, 2, 1
Analyzing [ () apathy]
String ' () apathy' is misformatted: it has extra characters after an empty list
List contents (0):
Analyzing [ (3,X,1)]
String ' (3,X,1)' is misformatted: it is incorrectly formatted
List contents (1): 3
Analyzing [ (3X,1)]
String ' (3X,1)' is misformatted: it does not start correctly
List contents (0):