qfedu-c-level/day11/homework/h4.c

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// 编写一个程序要求用户输入一串字符然后动态创建一个字符数组并将用户输入的字符存储到数组中。然后使用realloc函数将数组的大小扩展为原来的两倍并继续接受用户输入的字符直到用户输入字符为换行符 '\n')。最后,打印数组中存储的所有字符。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *
str_cpy(char *dest, const char *src)
{
int cnt;
while (src[cnt++])
;
char *res = (char *)malloc(cnt * sizeof(char *));
if (NULL == res)
{
perror("malloc");
exit(0);
}
for (int i = 0; i < cnt; i++)
res[i] = src[i];
return res;
}
int main()
{
char s1[100]; // 相当于 char *s1 = (char *)malloc(100 * sizeof(char *));
printf("请输入一个字符串: ");
// scanf("%s", s1);
fgets(s1, sizeof(s1), stdin); // scanf() 不能接收换行,故改用 fgets()
char *s2 = str_cpy(s2, s1);
int tmp_size = strlen(s2);
// 扩展数组大小
s2 = (char *)realloc(s2, 2 * tmp_size);
if (NULL == s2)
{
perror("realloc");
exit(0);
}
printf("请继续输入字符, 输入换行符结束输入\n");
char *ch;
s2[tmp_size - 1] = ' ';
while ((ch = getchar()) != '\n')
{
s2[tmp_size++] = ch;
}
printf("结果为: %s\n", s2);
free(s2);
return 0;
}