重载运算符加减乘除170312

 1 #include <cstdio>
 2 #include <cstring>
 3 //2017.3.12
 4 int max(int a,int b){return a >= b ? a : b;}
 5 struct bignum{
 6     int data[1001],len;
 7     bignum(){len = 1;memset(data,0,sizeof(data));}
 8 };
 9 void operator==(bignum &a,int b){ 
10     int t,i = 0;
11     int tmp[1001];
12     while(b > 0){
13         i++;
14         t = b % 10;
15         tmp[i] = t;
16         b = (b - t) / 10;
17     }
18     for(int j = 1;j <= i;j++){
19         a.data[j] = tmp[j];
20     }
21     a.len = i;
22 }
23 bignum operator-(bignum a,bignum b){
24     bignum c;
25     c.len = max(a.len,b.len);
26     for(int i = 1;i <= c.len;i++){
27         if(a.data[i] < b.data[i])
28             a.data[i] += 10,a.data[i + 1]--;
29         c.data[i] = a.data[i] - b.data[i];
30     }
31     if(c.data[c.len] == 0)c.len--;
32     return c;
33 }
34 void operator-=(bignum &a,bignum b){
35     a = a - b;
36 }
37 bignum operator/(bignum a,int b){
38     int d = 0;
39     for(int i = a.len;i >= 1;i--) 
40     {
41         d = d * 10 + a.data[i]; 
42         a.data[i] = d / b;
43         d = d % b; 
44     }
45     while(a.data[a.len] == 0 && a.len > 1) a.len--; 
46     return a;
47 }
48 void operator/=(bignum &a,int b){
49     a = a / b;
50 }
51 bignum operator+(bignum a,bignum b){
52     bignum c;
53     c.len = max(a.len,b.len);
54     for(int i = 1;i <= c.len;i++){
55         c.data[i] += a.data[i] + b.data[i];
56         if(c.data[i] >= 10){
57             c.data[i] %= 10;
58             c.data[i + 1]++;
59         }
60     }
61     if(c.data[c.len + 1] > 0)c.len++;
62     return c;
63 }
64 void operator+=(bignum &a,bignum b){
65     a = a + b;
66 }
67 bignum operator*(bignum a,bignum b){
68     bignum c;
69     c.len = a.len + b.len;
70     for(int i = 1;i <= a.len;i++){
71         for(int j = 1;j <= b.len;j++){
72             c.data[i+j-1] += a.data[i] * b.data[j];
73             if(c.data[i+j-1] >= 10){
74                 c.data[i+j] += c.data[i+j-1] / 10;
75                 c.data[i+j-1] %= 10;
76             }
77         }
78     }
79     if(c.data[c.len] == 0)c.len--;
80     return c;
81 }
82 void operator*=(bignum &a,bignum b){
83     a = a * b;
84 }
85 void get(bignum &a){
86     char x[10001];
87     scanf("%s",x + 1);a.len = strlen(x + 1);
88     for(int i = 1;i <= a.len;i++){
89         a.data[a.len - i + 1] = x[i] - '0';
90     }
91 }
92 void put(bignum a){
93     for(int i = a.len;i >= 1;i--)
94         printf("%d",a.data[i]);
95 }