1020題

#include "stdio.h"
void func(char*,int,int);
int main()
{
	int carry, howlong, dot=0;
	char a[100] = { '\0' };
	while (scanf("%s", a) != EOF&&scanf("%d", &carry) != EOF)
	{
		if (a[0] == '-'&&a[1] == '0'&&a[2]=='\0')
		{
			puts("0");
			continue;
		}
		for (int i = 0; i < 100; i++)

		{
			if (a[i] == '.')
			{
				dot = i;
				howlong = dot + carry + 1;
				if (a[howlong] - '0' >= 5)//過5進位
				{
					if (carry == 0)//四捨五入到第0位
					{
						howlong--;//前一位為小數點
						a[howlong] = '\0';
					}
					a[howlong - 1] ++;
					a[howlong] = '\0';
					howlong--;
					break;
				}
				else //沒過5
				{
					if (carry == 0)
					{
						howlong--;//<<小數點
						a[howlong] = '\0';
					}
					else
					{
						a[howlong] = '\0';
					}
				}
			}
		}
		if (dot == 0)//無小數位元
		{

				puts(a);
			continue;
		}
		for (int i = howlong; i >= 0; i--)
		{
			if (a[i] == 58 && i == 1)//前一位進為第二位
			{
				a[i] = '0';
				if (a[i - 1] == '-')//第一位為負
				{
					a[i - 1] = '1';
					func(a,howlong,dot);
					printf("-");
					puts(a);
					break;
				}
				else if (a[i - 1] == '9')//第一位為9
				{
					func(a,howlong,dot);
					a[i - 1] = '0';
					printf("1");
					puts(a);
					break;
				}
				else//第一位非負非9

				{
					a[i - 1]++;
					func(a,howlong,dot);
					if (dot == 1)
					{
						printf("10");
						break;
					}
					puts(a);
					break;
				}
			}
			else if (a[i] == 58 && a[i - 1]<58 && a[i - 1] >= 48)//前一位進位
			{
				a[i] = '0';
				a[i - 1]++;
			}
			else if (a[i] == 58 && a[i - 1] == '.')//前一位進為且欲小數點
			{
				i--;
				a[i] = '\0';
				a[i - 1]++;
			}
			else
			{
				func(a,howlong,dot);
				if (dot == 1&&a[0]==58)
				{
					puts("10");
					break;
				}
				puts(a);
				break;
			}
		}
	}
	return 0;
}
void func(char *address,int howlong,int dot)	//刪去尾部多餘之0
{
	for (int i = 100; i >= 0; i--)
	{

		if (*(address + i) != '0'&&*(address + i) != '\0'&&i<=howlong&&*(address + i) != '.'||i==dot-1)break;
		*(address + i) = '\0';
	}
}