乘法运算

模拟题，非大数乘法运算；

解析：细节比较多，我是用int型数组进行存储，如果用字符型存储，则需要考虑前缀0的情况；

   一、当计算过程中出现运算结果为0时，此时0的位数为1，如果按照常规处理，长度（即位数）就为0；

   二、当n和m中任意一个数为0，或者当m为个位数时，直接输出结果，不需要输出中间过程；

   三、当n和m中出现负数时或者在运算过程中出现负数情况时，注意减去负数的长度；

#include<iostream>
#include<cstdio>
#include<cmath>

using namespace std;

const int maxn = 10005;
int num1[ maxn ], num2[ maxn ];
int main(){
	int Case, n, m, len, sum, ans, len1, len2, len3, temp, tempn, tempm;
	cin >> Case;
	while( Case-- ){
		cin >> n >> m;
		
		sum = n * m;
		//cout << sum << endl;
		tempn = n, tempm = m;
		len = 0;
		
		/*1*/
		int k = 0, k1 = 0, k2 = 0;
		if( n <= 0 ) 
			k1 = 1;
		
		while( n ){
			num1[ k1++ ] = n % 10;
			n /= 10;
		}
		k2 = 0;
		if( m <= 0 )
			k2 = 1;
		
			while( m ){
				num2[ k2++ ] = m % 10;
				m /= 10;
			}
		/*1*/
		
		/*2*/
			len = 8;
			if( tempn < 0 )
				k1 + 1;
			len1 = len - k1;
			while( len1-- ){
				cout << " ";
			}
			cout << tempn << endl;
			len1 = len - k2 - 1;
			cout << "x";
			while( len1-- ){
				cout << " ";
			}
			cout << tempm << endl;
			/*2*/
			
			/*3*/
		if( k2 > 1 ){
			cout << "--------" << endl;
			k = max( k1, k2 );
			ans = 0;
			for( int i = 0; i < k2; ++i ){			
				temp = num2[ i ] * tempn;
				int t = temp;
				
				//cout << temp << endl;  
				if( t <= 0 )
					len3 = 1;
				else
					len3 = 0; 
				while( t ){
					len3++;
					t /= 10;
				}
				//cout << len3 << "aaaaaaaaaaaaaaaaa" << endl;
				/*空格*/
				len2 = len - ans - len3;
				
				/*单行输出*/ 
	
				while( len2-- )
					cout << " ";
				cout << temp << endl;
				/*某位空格数 */
				ans++;
				
				//cout << ans << "aaaaaaaaaaaaaaaa" << endl; 
			}
		}
		/*3*/
	
		/*4*/
		cout << "--------" << endl;
		len = 0;
		if( sum <= 0  )
			len = 1;
		while( sum ){
			len++;
			sum /= 10;
		}
		len = 8 - len;
		while( len-- )
			cout << " ";
		cout << tempn * tempm << endl;
		cout << "********************" << endl;
		/*4*/ 
	}
	return 0;
}

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乘法运算

原文：http://blog.csdn.net/bo_jwolf/article/details/20004505