我不太清楚为什么较大的字符串("cat"和"dog")的答案不一致.我正在使用链接列表和模板的使用做一些事情.我的好奇心让我修改了模板和函数重载.如果有人能解释发生了什么,我将不胜感激.谢谢.
#includeusing namespace std; // for the sake of simplicity. (otherwise, std::) // Function overloading and the use of templates // overloading the function larger int larger(int, int); char larger(char, char); double larger(double, double); string larger(string, string); template elementType anyLarger(elementType parameter1, elementType parameter2); int main() { cout << endl; cout << "Function Overloading" << endl; cout << "larger(15, 27) = " << larger(15, 27) << endl; cout << "larger('X', 'P') = " << larger('X', 'P') << endl; cout << "larger(4.9, 3.2) = " << larger(4.9, 3.2) << endl; cout << "larger(cat, dog) = " << larger("cat", "dog") << endl; cout << endl; cout << "Using the function template to find the larger of two items" << endl; cout << "anyLarger(15, 27) = " << anyLarger(15, 27) << endl; cout << "anyLarger('X', 'P') = " << anyLarger('X', 'P') << endl; cout << "anyLarger(4.9, 3.2) = " << anyLarger(4.9, 3.2) << endl; cout << "anyLarger(cat, dog) = " << anyLarger("cat", "dog") << endl; cout << endl; cout << "Compare two strings: cat, dog" << endl; if ("cat" >= "dog") { cout << "cat is greater than dog" << endl; } else { cout << "dog is greater than cat" << endl; } cout << endl; string strCat = "cat"; string strDog = "dog"; cout << "string strCat = cat" << endl; cout << "string strDog = dog" << endl; if (strCat >= strDog) { cout << "strCat is greater than strDog" << endl; } else { cout << "strDog is greater than strCat" << endl; } cout << endl; } // end main // Overloading larger int larger(int x, int y) { if (x >= y) return x; else return y; } char larger(char a, char b) { if (a >= b) return a; else return b; } double larger(double p, double q) { if (p >= q) return p; else return q; } string larger(string y, string z) { if (y >= z) return y; else return z; } // Defining the template function template elementType anyLarger(elementType parameter1, elementType parameter2) { if (parameter1 >= parameter2) return parameter1; else return parameter2; }
这是运行程序后的结果.
Function Overloading
larger(15, 27) = 27
larger('X', 'P') = X
larger(4.9, 3.2) = 4.9
larger(cat, dog) = dog
Using the function template to find the larger of two items
anyLarger(15, 27) = 27
anyLarger('X', 'P') = X
anyLarger(4.9, 3.2) = 4.9
anyLarger(cat, dog) = cat
Compare two strings: cat, dog
cat is greater than dog
string strCat = cat
string strDog = dog
strDog is greater than strCat
==============================================
更新:进行了一些更改并使用了strcmp#include#include using namespace std; // Function overloading and the use of templates // overloading the function larger int larger(int, int); char larger(char, char); double larger(double, double); string larger(string, string); template elementType anyLarger(elementType parameter1, elementType parameter2); int main(){ cout << endl; cout << "// Function Overloading" << endl; cout << "larger(15, 27) = " << larger(15, 27) << endl; cout << "larger('X', 'P') = " << larger('X', 'P') << endl; cout << "larger(4.9, 3.2) = " << larger(4.9, 3.2) << endl; cout << "larger(\"cat\", \"dog\") = " << larger("cat", "dog") << endl; cout << endl; cout << "// Using the function template to find the larger of two items" << endl; cout << "anyLarger(15, 27) = " << anyLarger(15, 27) << endl; cout << "anyLarger('X', 'P') = " << anyLarger('X', 'P') << endl; cout << "anyLarger(4.9, 3.2) = " << anyLarger(4.9, 3.2) << endl; cout << "anyLarger(\"cat\", \"dog\") = " << anyLarger("cat", "dog") << endl; cout << endl; cout << "// Compare two strings using >= : \"cat\", \"dog\"" << endl; if ("cat" >= "dog") { cout << "\"cat\" is greater than \"dog\"" << endl; } else { cout << "\"dog\" is greater than \"cat\"" << endl; } cout << endl; cout << "// The use of variables: strCat and strDog. Compare using >=" << endl; string strCat = "cat"; string strDog = "dog"; cout << "string strCat = \"cat\";" << endl; cout << "string strDog = \"dog\";" << endl; if (strCat >= strDog) { cout << "strCat is greater than strDog" << endl; } else { cout << "strDog is greater than strCat" << endl; } cout << endl; cout << "// Using strcmp. strcmp(\"cat\", \"dog\")" << endl; int result = strcmp("cat", "dog"); if (result > 0) { cout << "\"cat\" is greater than \"dog\"" << endl; } else { cout << "\"dog\" is greater than \"cat\"" << endl; } } // Overloading larger int larger(int x, int y) { if (x >= y) return x; else return y; } char larger(char a, char b) { if (a >= b) return a; else return b; } double larger(double p, double q) { if (p >= q) return p; else return q; } string larger(string y, string z) { if (y >= z) return y; else return z; } // Defining the template function template elementType anyLarger(elementType parameter1, elementType parameter2) { if (parameter1 >= parameter2) return parameter1; else return parameter2; }
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更新:输出// Function Overloading
larger(15, 27) = 27
larger('X', 'P') = X
larger(4.9, 3.2) = 4.9
larger("cat", "dog") = dog
// Using the function template to find the larger of two items
anyLarger(15, 27) = 27
anyLarger('X', 'P') = X
anyLarger(4.9, 3.2) = 4.9
anyLarger("cat", "dog") = cat
// Compare two strings using >= : "cat", "dog"
"cat" is greater than "dog"
// The use of variables: strCat and strDog. Compare using >=
string strCat = "cat";
string strDog = "dog";
strDog is greater than strCat
// Using strcmp. strcmp("cat", "dog")
"dog" is greater than "cat"
Jon.. 10
在两种情况下,您都不会按字典顺序比较字符串.
"cat" >= "dog"
这是比较char指针,因为文字的类型"cat"和"dog"为const char*.它可以给出任何结果,具体取决于编译器如何决定实现文字.
要按字典顺序比较C风格的字符串(包括这些字符串),strcmp必须使用该函数.
strCat >= strDog
这是按字典顺序比较字符串,因为std::string它提供了明确实现此类比较的比较运算符.
在两种情况下,您都不会按字典顺序比较字符串.
"cat" >= "dog"
这是比较char指针,因为文字的类型"cat"和"dog"为const char*.它可以给出任何结果,具体取决于编译器如何决定实现文字.
要按字典顺序比较C风格的字符串(包括这些字符串),strcmp必须使用该函数.
strCat >= strDog
这是按字典顺序比较字符串,因为std::string它提供了明确实现此类比较的比较运算符.
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