我想更改特定字符串中的数字。例如,如果我有字符串“GenLabel2”,我想将其更改为“GenLabel0”。我正在寻找的解决方案不仅仅是简单地将字符从 2 更改为 0,而是使用算术方法。
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1 回答
1
此方法适用于大于 9 的数字。它采用字符串中最右边的数字,并向其添加任意数字(从命令行读取)。字符串中的数字假定为正数。
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#define LABEL_MAX 4096
char *find_last_num(char *str, size_t size)
{
char *num_start = (char *)NULL;
char *s;
/* find the start of the last group of numbers */
for (s = str + size - 1; s != str; --s)
{
if (isdigit(*s))
num_start = s;
else if (num_start)
break; /* we found the entire number */
}
return num_start;
}
int main(int argc, char *argv[])
{
char label[LABEL_MAX] = "GenLabel2";
size_t label_size;
int delta_num;
char *num_start;
int num;
char s_num[LABEL_MAX];
/* check args */
if (argc < 2)
{
printf("Usage: %s delta_num\n", argv[0]);
return 0;
}
delta_num = atoi(argv[1]);
/* find the number */
label_size = strlen(label);
num_start = find_last_num(label, label_size);
/* handle case where no number is found */
if (!num_start)
{
printf("No number found!\n");
return 1;
}
num = atoi(num_start); /* get num from string */
*num_start = '\0'; /* trim num off of string */
num += delta_num; /* change num using cl args */
sprintf(s_num, "%d", num); /* convert num to string */
strncat(label, s_num, LABEL_MAX - label_size - 1); /* append num back to string */
label[LABEL_MAX - 1] = '\0';
printf("%s\n", label);
return 0;
}
于 2013-05-05T00:59:17.557 回答