UVa 10035 Primary Arithmetic (陷阱较多~)

10035 - Primary Arithmetic

Time limit: 3.000 seconds

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=976

Children are taught to add multi-digit numbers from right-to-left one digit at a time. Many find the "carry" operation - in which a 1 is carried from one digit position to be added to the next - to be a significant challenge. Your job is to count the number of carry operations for each of a set of addition problems so that educators may assess their difficulty.

Input

Each line of input contains two unsigned integers less than 10 digits. The last line of input contains 0 0.

Output

For each line of input except the last you should compute and print the number of carry operations that would result from adding the two numbers, in the format shown below.

Sample Input

123 456
555 555
123 594
0 0

Sample Output

No carry operation.
3 carry operations.
1 carry operation.

有至少两个陷阱吧，详见注释。

完整代码：

/*0.019s*/

#include <cstdio>

int main(void)
{
	int a, b;
	int carry, c;///carry表示进位数
	while (scanf("%d%d", &a, &b) , a + b)
	{
		carry = c = 0;
		while (a || b) ///注意999+1的情况~
		{
			c = (a % 10 + b % 10 + c) > 9 ? 1 : 0;
			carry += c;///或者写if(c) ++carry;
			a /= 10;
			b /= 10;
		}
		if (carry == 0)
			puts("No carry operation.");
		else if (carry == 1)
			puts("1 carry operation.");
		else
			printf("%d carry operations.\n", carry);
	}
	return 0;
}