105 lines
4.2 KiB
C++
105 lines
4.2 KiB
C++
// fig11_01.cpp
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// Standard library string class test program.
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#include <fmt/format.h>
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#include <iostream>
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#include <string>
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#include <string_view>
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int main() {
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std::string s1{"happy"}; // initialize string from char*
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std::string s2{" birthday"}; // initialize string from char*
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std::string s3; // creates an empty string
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std::string_view v{"hello"}; // initialize string_view from char*
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// output strings and string_view
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std::cout << "s1: \"" << s1 << "\"; s2: \"" << s2
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<< "\"; s3: \"" << s3 << "\"; v: \"" << v << "\"\n\n";
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// test overloaded equality and relational operators
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std::cout << "The results of comparing s2 and s1:\n"
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<< fmt::format("s2 == s1: {}\n", s2 == s1)
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<< fmt::format("s2 != s1: {}\n", s2 != s1)
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<< fmt::format("s2 > s1: {}\n", s2 > s1)
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<< fmt::format("s2 < s1: {}\n", s2 < s1)
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<< fmt::format("s2 >= s1: {}\n", s2 >= s1)
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<< fmt::format("s2 <= s1: {}\n\n", s2 <= s1);
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// test string member function empty
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std::cout << "Testing s3.empty():\n";
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if (s3.empty()) {
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std::cout << "s3 is empty; assigning s1 to s3;\n";
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s3 = s1; // assign s1 to s3
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std::cout << fmt::format("s3 is \"{}\"\n\n", s3);
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}
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// test overloaded string concatenation assignment operator
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s1 += s2; // test overloaded concatenation
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std::cout << fmt::format("s1 += s2 yields s1 = {}\n\n", s1);
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// test string concatenation with a C string
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s1 += " to you";
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std::cout << fmt::format("s1 += \" to you\" yields s1 = {}\n\n", s1);
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// test string concatenation with a C++14 string-object literal
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using namespace std::string_literals;
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s1 += ", have a great day!"s; // s after " for string-object literal
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std::cout << fmt::format(
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"s1 += \", have a great day!\"s yields\ns1 = {}\n\n", s1);
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// test string member function substr
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std::cout << fmt::format("{} {}\n{}\n\n",
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"The substring of s1 starting at location 0 for",
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"14 characters, s1.substr(0, 14), is:", s1.substr(0, 14));
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// test substr "to-end-of-string" option
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std::cout << fmt::format("{} {}\n{}\n\n",
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"The substring of s1 starting at",
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"location 15, s1.substr(15), is:", s1.substr(15));
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// test copy constructor
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std::string s4{s1};
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std::cout << fmt::format("s4 = {}\n\n", s4);
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// test overloaded copy assignment (=) operator with self-assignment
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std::cout << "assigning s4 to s4\n";
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s4 = s4;
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std::cout << fmt::format("s4 = {}\n\n", s4);
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// test string's string_view constructor
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std::cout << "initializing s5 with string_view v\n";
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std::string s5{v};
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std::cout << fmt::format("s5 is {}\n\n", s5);
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// test using overloaded subscript operator to create lvalue
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s1[0] = 'H';
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s1[6] = 'B';
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std::cout << fmt::format("{}:\n{}\n\n",
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"after s1[0] = 'H' and s1[6] = 'B', s1 is", s1);
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// test index out of range with string member function "at"
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try {
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std::cout << "Attempt to assign 'd' to s1.at(100) yields:\n";
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s1.at(100) = 'd'; // ERROR: subscript out of range
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}
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catch (const std::out_of_range& ex) {
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std::cout << fmt::format("An exception occurred: {}\n", ex.what());
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}
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}
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/**************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The authors *
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* and publisher shall not be liable in any event for incidental or *
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* consequential damages in connection with, or arising out of, the *
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* furnishing, performance, or use of these programs. *
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**************************************************************************/
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