大数求差——（华为实习招聘机试题）

  1 #include "stdafx.h"
  2 #include<iostream>
  3 
  4 using namespace std;
  5 
  6 unsigned int len1 = 0, len2 = 0, len3 = 0;
  7 
  8 char flag = 0;
  9 
 10 int main(void)
 11 {
 12     char num1[100] = { 0 };
 13     char num2[100] = { 0 };
 14     char temp[100] = { 0 };
 15 
 16     cin >> num1 >> num2;
 17 
 18     len1 = strlen(num1);
 19     len2 = strlen(num2);
 20 
 21     if (len1 > len2 || (len1 == len2&&strcmp(num1, num2) >= 0))
 22     {    
 23         int i, j;
 24         for (i = len1 - 1, j = len2 - 1; (i >= 0 && j >= 0); i--, j--)
 25         {
 26             if (num1[i] >= num2[j])
 27             {
 28                 temp[i] = num1[i] - num2[j] + '0';
 29             }
 30             else
 31             {
 32 
 33                 temp[i] = num1[i] + 10 - num2[j] + '0';
 34                 num1[i - 1] -= 1;
 35             }
 36 
 37         }
 38         for (; i >= 0; i--)
 39         {
 40             temp[i] = num1[i];
 41         }
 42         flag = 0;
 43     }
 44     else
 45     {
 46         int i, j;
 47         for (i = len1 - 1, j = len2 - 1; (i >= 0 && j >= 0); i--, j--)
 48         {
 49             if (num1[i] <= num2[j])
 50             {
 51                 temp[j] = num2[j] - num1[i] + '0';
 52             }
 53             else
 54             {
 55                 temp[j] = num2[j] + 10 - num1[i] + '0';
 56                 num2[j - 1] -= 1;
 57             }
 58         }
 59         for ( ; j >= 0; j--)
 60         {
 61             temp[j] = num2[j];
 62         }
 63         flag = 1;
 64     }
 65     if (flag == 1)
 66     {
 67         cout << "-";
 68     }
 69     len3 = strlen(temp);
 70     int i = 0;
 71     while (temp[i] == '0')
 72     {
 73         i++;
 74         if (i == len3)
 75         {
 76             cout << "0";
 77             return 0;
 78         }
 79         
 80     }
 81 
 82     for (; i < len3; i++)
 83     {
 84         cout << temp[i];
 85     }
 86 
 87     return 0;
 88 }
 89 
 90 #include "stdafx.h"
 91 #include<iostream>
 92 #include<string>
 93 
 94 using namespace std;
 95 
 96 unsigned int len1 = 0, len2 = 0, len3 = 0;
 97 
 98 char flag = 0;
 99 
100 int main(void)
101 {
102     string num1 = "";
103     string num2 = "";
104     string temp = "";
105 
106     cin >> num1 >> num2;
107 
108     len1 = num1.length();
109     len2 = num2.length(); 
110     if (len1 < len2 || (len1 == len2 && num1 < num2))
111     {
112         temp = num1;
113         num1 = num2;
114         num2 = temp;
115         len1 = num1.length();
116         len2 = num2.length();
117         flag = 1;
118     }
119     int i, j;
120     for (i = len1 - 1, j = len2 - 1; (i >= 0 && j >= 0); i--, j--)
121     {
122         if (num1[i] >= num2[j])
123         {
124             num1[i] = num1[i] - num2[j] + '0';
125         }
126         else
127         {
128 
129             num1[i] = num1[i] + 10 - num2[j] + '0';
130             num1[i - 1] -= 1;
131         }
132 
133     }
134     
135     if (flag == 1)
136     {
137         cout << "-";
138     }
139      i = 0;
140     while (num1[i] == '0')
141     {
142         i++;
143         if (i == len1)
144         {
145             cout << "0";
146             return 0;
147         }
148 
149     }
150 
151     for (; i < len1; i++)
152     {
153         cout << num1[i];
154     }
155 
156     return 0;
157 }