char* insert按顺序插入字符(char* str, char c)
{//缘由https://ask.youkuaiyun.com/questions/7449243?spm=1005.2025.3001.5141
char t;
while (*str != '\0')//while (*str != '\n')
if (*str < c)
++str;
else
t = *str, *str = c, c = t, ++str;
*str = c;
return str;
}
char a[54]{}, c;//"abdef"
int x = 0;
while (1)
{
scanf_s("%c", &a[x]);
if (a[x] == '\n')
break;
else
++x;
}
a[x] = '\0';//使用'\n'退出时不用这句
scanf_s("%c", &c);
insert按顺序插入字符(a, c); x = 0;
while (a[x] != '\0')printf_s("%c", a[x++]);
printf_s("\n");

char* insert按顺序插入字符(char* str, char c)
{//缘由https://ask.youkuaiyun.com/questions/7449243?spm=1005.2025.3001.5141
char t;
while (*str != '\0')
if (*str < c)
++str;
else
t = *str, *str = c, c = t, ++str;
*str = c; ++*str='\0';
return str;
//char a[54]{0}, c;//"abdef"
//int x = 0;
//scanf_s("%s", a, 54);
//getchar();
//scanf_s("%c", &c);
//insert按顺序插入字符(a, c);
//while (a[x] != '\0')printf_s("%c", a[x++]);
//printf_s("\n");
}