feat(calc_lib): 大数除法, 只实现了整数

calc_lib/include/khl_calc/khl_calc_decimal.h

@@ -14,6 +14,16 @@ public:
     std::string substract(std::string x, std::string y);
 
     std::string multiply(std::string x, std::string y);
+
+    std::string divide(std::string x, std::string y);
+
+    const int compare(std::string x, std::string y);
+private:
+
+    /**
+     * 比较两个数字的大小
+     */
+    // const int compare(std::string x, std::string y);
 };
 KHL_CALC_NAMESPACE_END
 #endif // _KHL_CALC_DECIMAL_H_
\ No newline at end of file

calc_lib/src/khl_calc/khl_calc_decimal.cpp

@@ -204,12 +204,12 @@ std::string Decimal::multiply(std::string x, std::string y)
 
     for (int i = 1; i < la; i++)
     {
-        a[la - i] = sx[i-1] - '0';
+        a[la - i] = sx[i - 1] - '0';
     }
 
     for (int i = 1; i < lb; i++)
     {
-        b[lb - i] = sy[i-1] - '0';
+        b[lb - i] = sy[i - 1] - '0';
     }
 
     /** 计算 */
@@ -228,7 +228,7 @@ std::string Decimal::multiply(std::string x, std::string y)
     /** 翻转计算结果 */
     std::string str;
     int i = lc - 1;
-    while( 0 == c[i] && i > 1)
+    while (0 == c[i] && i > 1)
     {
         i--;
     }
@@ -241,4 +241,64 @@ std::string Decimal::multiply(std::string x, std::string y)
     return str;
 }
 
+std::string Decimal::divide(std::string x, std::string y)
+{
+    if (0 == x.compare("0") || compare(x,y) < 0)
+    {
+        return "0";
+    }
+
+    if(0 == compare(x,y) )
+    {
+        return "1";
+    }
+
+    /**
+     * 字符串转换为倒置的 int 数组
+     * x = 123 , y = 4567
+     * x = 321 , y = 7654
+     */
+    char *sx = const_cast<char *>(x.c_str());
+    char *sy = const_cast<char *>(y.c_str());
+    const size_t la = x.size() + 1;
+    const size_t lb = y.size() + 1;
+    auto a = std::make_unique<int[]>(la);
+    auto b = std::make_unique<int[]>(lb);
+
+    for (int i = 1; i < la; i++)
+    {
+        a[la - i] = sx[i - 1] - '0';
+    }
+
+    for (int i = 1; i < lb; i++)
+    {
+        b[lb - i] = sy[i - 1] - '0';
+    }
+
+    std::string str = "0";
+
+    // 余数
+    std::string remainder = x;
+    while (compare(remainder, y) >= 0)
+    {
+        remainder = substract(remainder,y);
+        str = add(str,"1");
+    }
+
+    return str;
+}
+
+const int Decimal::compare(std::string x, std::string y)
+{
+    if (x.size() < y.size())
+    {
+        return -1;
+    }
+    if (x.size() > y.size())
+    {
+        return 1;
+    }
+    return x.compare(y);
+}
+
 KHL_CALC_NAMESPACE_END

calc_lib/src/main/main.cpp

@@ -5,10 +5,12 @@
 int main()
 {
     auto decimal = std::make_unique<khl::calc::Decimal>();
-    for (int i = 0; i < 10; i++)
-    {
-        std::cout << decimal->add("465465465464", "1321654876135138468135135") << std::endl;
+    // for (int i = 0; i < 10; i++)
+    // {
+
+        // std::cout << decimal->divide("531518", "123") << std::endl;
+        std::cout << decimal->divide("9999", "2") << std::endl;
         std::cout << "===================" << std::endl;
-    }
+    // }
     return 0;
 }
\ No newline at end of file

calc_lib/test/testmain.cpp

@@ -41,8 +41,19 @@ TEST_CASE("test_multiply")
     auto decimal = std::make_unique<khl::calc::Decimal>();
 
     std::cout << decimal->multiply("9133", "0") << std::endl;
-    
 }
 
+TEST_CASE("test_divide")
+{
+    spdlog::info("test divide");
+    auto decimal = std::make_unique<khl::calc::Decimal>();
 
+    // std::cout << decimal->divide("10", "5") << std::endl;
+    // std::cout << decimal->divide("531518", "123") << std::endl;
+    std::cout << decimal->divide("9999", "2") << std::endl;
+    std::cout << decimal->divide("99999", "2") << std::endl;
+    std::cout << decimal->divide("999999", "2") << std::endl;
+    std::cout << decimal->divide("9999999", "2") << std::endl;
+
+}