c-resources/CPlusPlus20ForProgrammers-m.../examples/ch08/fig08_01.cpp

48 lines
2.1 KiB
C++

// fig08_01.cpp
// Demonstrating string assignment and concatenation.
#include <fmt/format.h>
#include <iostream>
#include <string>
int main() {
std::string s1{"cat"};
std::string s2; // initialized to the empty string
std::string s3; // initialized to the empty string
s2 = s1; // assign s1 to s2
s3.assign(s1); // assign s1 to s3
std::cout << fmt::format("s1: {}\ns2: {}\ns3: {}\n\n", s1, s2, s3);
s2.at(0) = 'r'; // modify s2
s3.at(2) = 'r'; // modify s3
std::cout << fmt::format("After changes:\ns2: {}\ns3: {}", s2, s3);
std::cout << "\n\nAfter concatenations:\n";
std::string s4{s1 + "apult"}; // concatenation
s1.append("acomb"); // create "catacomb"
s3 += "pet"; // create "carpet" with overloaded +=
std::cout << fmt::format("s1: {}\ns3: {}\ns4: {}\n", s1, s3, s4);
// append locations 4 through end of s1 to
// create string "comb" (s5 was initially empty)
std::string s5; // initialized to the empty string
s5.append(s1, 4, s1.size() - 4);
std::cout << fmt::format("s5: {}", s5);
}
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