字符串截取

有一个字符串是这样的：china中国verygood天朝nice,里面既含有中文又含义英文，请编写一个函数，能截取任意长度的字符串n(n<=总长度)

例：

fn(5) = china

fn(6) = china中

fn(8) = china中国v

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>


char *func(char *str, int l) {
	char *p = str;
	printf("%s\n", p);
	char *new_str = (char *)malloc(sizeof(char *) * strlen(str) + 1);
	printf("%d\n", strlen(str) + 1);
	if (!new_str) {
		printf("error");
	}
	char *str1 = new_str;
	*new_str = *p;
	//printf();
	while (l--) {
		if (*p >= 0) {
			*new_str++ = *p++;
			/**new_str = *p;
			new_str++;
			p++;*/
		}
		else if (*p < 0) {
			*new_str++ = *p++;
			*new_str++ = *p++;
			/**new_str = *p;
			new_str++;
			p++;
			*new_str = *p;
			new_str++;
			p++;*/
		}
	}
	*new_str = 0;
	return str1;
}

int main(int argc, char *argv[])
{
	char *str = (char *)malloc(sizeof(char *) * 32);
	char *str1 = "china中国nice";
	memcpy(str, str1, strlen(str1) + 1);
	printf("%s\n", func(str, 7));
	//func(str, 7);

	system("pause");
	return 0;
}