数据结构与算法(0)-四则运算

偏执的太偏执、 2022-10-03 00:41 147阅读 0赞

# 数据结构算法(0)--大数运算 #

总结并记录学习数据结构过程中遇到的问题及算法.

--------------------

一些常见算法：

> **Note:**

>  *  大数四则运算.

#### 加法 ####

#include <iostream>
    #include<string>
    #include<stdio.h>
    using namespace std;
    
    #define MAXSIZE 1000
    int num1[MAXSIZE], num2[MAXSIZE];
    
    void sum(char a[], char b[])
    {
        int len1 = strlen(a);
        int len2 = strlen(b);
        int i, j;
    
        int lensum = len1 > len2 ? len1 : len2;  //总计算长度
        lensum++;
        for (i = len1 - 1, j = 0; i >= 0; --i)    //逆序存储
        {
            num1[j++] = a[i] - '0';
        }
        for (i = len2 - 1, j = 0; i >= 0; --i)
        {
            num2[j++] = b[i] - '0';
        }
        for (i = 0; i < lensum; ++i)
        {
            int temp = num1[i] + num2[i];
            num1[i] = temp % 10;
            num1[i + 1] += temp / 10;
        }
        for (i = lensum - 1; i >= 0 && num1[i] == 0; --i);  //去除前置0
        
        if (i >= 0)
        {
            for (; i >= 0; --i)
                cout << num1[i];
        }
        else
            cout << 0;
        cout << endl;
    }
    
    int main()
    {
        
        char a[MAXSIZE], b[MAXSIZE];
        int i, j;
        cin >> a >> b;
        sum(a, b);
        system("pause");
    }

#### 减法 ####

#include <iostream>
    #include<string>
    #include<stdio.h>
    using namespace std;
    
    #define MAXSIZE 1000
    int num1[MAXSIZE], num2[MAXSIZE];
    bool myStrcmp(const char str1[], const char str2[])
    { 
        if (strlen(str1) > strlen(str2)) 
            return true; 
        if (strlen(str1) == strlen(str2))
                return strcmp(str1, str2) >= 0; 
        return false; 
    }
    void sum(char a[], char b[])
    {
        int len1 = strlen(a);
        int len2 = strlen(b);
        int i, j;
    
        int lensum = len1 > len2 ? len1 : len2;  //总计算长度
        lensum++;
        for (i = len1 - 1, j = 0; i >= 0; --i)    //逆序存储
        {
            num1[j++] = a[i] - '0';
        }
        for (i = len2 - 1, j = 0; i >= 0; --i)
        {
            num2[j++] = b[i] - '0';
        }
        for (i = 0; i < lensum; ++i)
        {
            num1[i] -= num2[i];
            if (num1[i] < 0)
            {
                num1[i] += 10;
                num1[i + 1]--;
            }
        }
        for (i = lensum - 1; i >= 0 && num1[i] == 0; --i);  //去除前置0
        
        if (i >= 0)
        {
            for (; i >= 0; --i)
                cout << num1[i];
        }
        else
            cout << 0;
        cout << endl;
    }
    
    int main()
    {
        
        char a[MAXSIZE], b[MAXSIZE];
        int i, j;
        cin >> a >> b;
        bool sign = myStrcmp(a, b);
        if (sign)
        {
            sum(a, b);
        }
        else
        {
            cout << '-';
            sum(b, a);
        }
        system("pause");
    }

#### 乘法 ####

#include <iostream>
    #include<string>
    #include<stdio.h>
    using namespace std;
    
    #define MAXSIZE 1000
    int num1[MAXSIZE], num2[MAXSIZE], num3[MAXSIZE*3];
    
    void sum(char a[], char b[])
    {
        int len1 = strlen(a);
        int len2 = strlen(b);
        int i, j;
    
        int lensum = len1 + len2 +1;  //总计算长度
        for (i = len1 - 1, j = 0; i >= 0; --i)    //逆序存储
        {
            num1[j++] = a[i] - '0';
        }
        for (i = len2 - 1, j = 0; i >= 0; --i)
        {
            num2[j++] = b[i] - '0';
        }
        for (i = 0; i < len1; ++i)   //计算
        {
            for (j = 0; j < len2; ++j)
            {
                num3[i + j] += num1[i] * num2[j];
            }
        }
        for (i = 0; i < lensum; ++i)   //处理进位
        {
            if (num3[i] >= 10)
            {
                num3[i + 1] += num3[i] / 10;
                num3[i] %= 10;
            }
        }
        for (i = lensum - 1; i >= 0 && num3[i] == 0; --i);  //去除前置0
        if (i >= 0)
        {
            for (; i >= 0; --i)
                cout << num3[i];
        }
        else
            cout << 0;
        cout << endl;
    }
    
    int main()
    {
        
        char a[MAXSIZE], b[MAXSIZE];
        int i, j;
        cin >> a >> b;
        sum(a, b);
        system("pause");
    }

#### 除法 ####

#include <iostream>
    #include<string>
    #include<stdio.h>
    using namespace std;
    
    #define MAXSIZE 5000
    char a[MAXSIZE], b[MAXSIZE];
    int result[MAXSIZE];
    
    void sub(char a[], char b[])  //正序相减
    {
        int i=0, j;
        int len2 = strlen(b);
        while (true)
        {
            if (a[i] == 0)
                ++i;
            else
            {
                j = i;
                break;
            }
        }
        for (; i < len2; ++i)
        {
            a[i] = a[i] - b[i] + '0';
        }
        for (i = len2 - 1; i > j; --i)
        {
            if (a[i] < '0')
            {
                a[i] += 10;
                a[i - 1]--;
            }
        }
    }
    
    int main()
    {
        int i = 0, j, pos;
        cin >> a >> b;
        int len1 = strlen(a);
        int len2 = strlen(b);
        if (len1 < len2 || (len1 == len2 && strcmp(a, b) < 0))
        {
            cout << i << " ";
            for (i = 0; i < len1; ++i)
                cout << a[i];
            cout << endl;
        }
        else
        {
            pos = 0;    //商的位数
            while (true)
            {
                result[pos] = 0;
                while (strcmp(a, b) >= 0)    //循环进行减法运算
                {
                    sub(a,b);
                    result[pos]++;
                }
                ++pos;
                if (len1 == len2)
                    break;
                for (i = len2 - 1; i >= 0; --i)
                    b[i + 1] = b[i];
                b[0] = '0';    //在除数前面补0，进行减法运算
                ++len2;
                b[len2] = '\0';
            }
            i = 0;
            while (result[i] == 0)   //去除商的前面0
                ++i;
            for (; i < pos; ++i)
                cout << result[i];
            j = 0;   //余数
            while (a[j] == '0')
                ++j;
            if (j == len1)
                cout << " " << 0 << endl;
            else
            {
                cout << " ";
                for (; j < len1; ++j)
                    cout << a[j] - '0';
                cout << endl;
            }
        }
        system("pause");
    }

转载于:https://www.cnblogs.com/willingtosmile/p/10471532.html