我一直在尝试使用C字符串对输入的数据进行排序。到目前为止，一切都很好，除非涉及情况3和4，也就是排序和显示排序后的数据，输出不是预期的。 显示的排序数据的输出仅给我
0 0 0 0 0 0 0 0 0 。 。 。 这是我第一次使用C字符串，但我仍然不太熟悉结构的概念。如果有人有其他方法，或者知道案例3/4的代码出了什么问题，请告诉我。谢谢
这是我的代码：
#include <iostream>
#include <string>
using namespace std;
struct sPlayer {
char lname[20];
char fname[20];
int birthmonth;
int birthday;
int birthyear;
};
int main()
{
int choice;
sPlayer players[10];
sPlayer sortedData[10];
while (true) {
cout << "Choose an option: " << endl;
cout << "1 - Input data, 2 - display original data, 3 -
sort data by last name,\n4 - display sorted data,
5 - search by
last name,\n6 - display goodbye message and exit the program " <<
endl;
cin >> choice;
switch (choice) {
case 1:
cout << "Enter data for 10 soccer players " << endl;
cout << "Enter in order: Last name, first name,(as integers) birth month, birthday, birth year, ";
cout << "separated by a space. Press [ENTER] to enter next player data. " << endl;
for(int i = 0; i < 10; i++)
{
cin >> players[i].lname;
cin >> players[i].fname;
cin >> players[i].birthmonth;
cin >> players[i].birthday;
cin >> players[i].birthyear;
}
break;
case 2:
cout << "Unsorted data: " << endl;
for (int i = 0; i < 10; i++) {
cout << players[i].lname << " "
<< players[i].fname << " " << players[i].birthmonth;
cout << " " << players[i].birthday << " " << players[i].birthyear << endl;
}
cout << endl;
break;
case 3:
sortedData[10] = players[10];
for (int i = 0; i < 9; i++) {
for (int j = i + 1; j < 10; j++) {
if (strcmp(sortedData[i].lname, sortedData[j].lname) > 0) {
char tempLastName[20];
char tempFirstName[20];
int tempBirthmonth;
int tempBirthday;
int tempBirthyear;
strcpy(tempLastName, sortedData[i].lname);
strcpy(sortedData[i].lname, sortedData[j].lname);
strcpy(sortedData[j].lname, tempLastName);
strcpy(tempFirstName, sortedData[i].fname);
strcpy(sortedData[i].fname, sortedData[j].fname);
strcpy(sortedData[j].fname, tempFirstName);
tempBirthmonth = sortedData[i].birthmonth;
sortedData[i].birthmonth = sortedData[j].birthmonth;
sortedData[j].birthmonth = tempBirthmonth;
tempBirthday = sortedData[i].birthday;
sortedData[i].birthday = sortedData[j].birthday;
sortedData[j].birthday = tempBirthday;
tempBirthyear = sortedData[i].birthyear;
sortedData[i].birthyear = sortedData[j].birthyear;
sortedData[j].birthyear = tempBirthyear;
}
}
}
break;
case 4:
cout << "Sorted data: " << endl;
for (int i = 0; i < 10; i++) {
cout << sortedData[i].lname << "
" << sortedData[i].fname << "
" << sortedData[i].birthmonth << "
"
<< sortedData[i].birthday << " " << sortedData[i].birthyear << endl;
}
cout << endl;
break;
case 5:
char searchString[20];
while (true) {
cout << "Enter one or more
starting letters of the last name(enter '//' to quit this option)
: " << endl;
cin
>> searchString;
if (strcmp(searchString, "//")
== 0)
break;
else {
int length = strlen(searchString);
strcat(searchString, "xx");
bool notFound = true;
for (int i = 0; i < 10; i++) {
if (strncmp(players[i].lname, searchString, length) == 0) {
cout << players[i].lname << " " << players[i].fname << " " << players[i].birthmonth << " " << players[i].birthday << " " << players[i].birthyear << endl;
notFound = false;
}
}
if (notFound) {
cout << "Not
found." << endl;
}
}
}
break;
case 6:
cout << "Good Bye " << endl;
break;
default:
cout << "Invalid Option , Try again" << endl;
}
if (choice == 6)
break;
}
return 0;
}
答案 0 :(得分：0)
通常最好将大问题分解为较小的问题。我建议使用子功能。
并且，您应该使用C ++ STL和算法。那很有帮助。你会看见。请勿使用char lname[20]或sPlayer players[10];之类的普通数组。请使用STL容器。它们可以成长，可以调整大小。它还可以大大减少您的复印工作。
使用面向对象的方法。数据和方法应归为一类。 sPlayer知道如何打印和阅读。因此，将这些方法添加到您的结构中。
您应该使用算法。像std::copy。这使生活更轻松。
您的帖子下方的评论中已经提到了错误。
请查看修改后的示例（一种可能性）：
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
#include <algorithm>
struct sPlayer {
// Data
std::string lname;
std::string fname;
unsigned int birthmonth;
unsigned int birthday;
unsigned int birthyear;
// Extractor operator
friend std::istream& operator >> (std::istream& is, sPlayer& sp) {
return is >> sp.lname >> sp.fname >> sp.birthmonth >> sp.birthday >> sp.birthyear;
}
// Inserter operator
friend std::ostream& operator << (std::ostream& os, const sPlayer& sp) {
return os << sp.fname << ' ' << sp.lname << ' ' << sp.birthmonth << '/' << sp.birthday << '/' << sp.birthyear;
}
};
constexpr int CmdInputData = 1;
constexpr int CmdDisplayOriginalData = 2;
constexpr int CmdSortByLastName = 3;
constexpr int CmdDisplaySortedData = 4;
constexpr int CmdSearchLastName = 5;
constexpr int CmdExit = 6;
// Read users choice. Check for valid data
int getMenuSelection()
{
std::cout << "\n\nChoose an option:\n 1 - Input Data\n 2 - Display original data\n" <<
" 3 - Sort data by last name\n 4 - Display sorted data\n 5 - Search by last name\n" <<
" 6 - Exit the program\n\n --> ";
// Here we will store the selection
int selection{ 0 };
// As long as there is no good selection, we will read a number
bool noGoodSelection = true;
while (noGoodSelection) {
// Read selection
std::cin >> selection;
// Check if valid
noGoodSelection = ((selection < CmdInputData) || (selection > CmdExit));
// If not, show message and read again
if (noGoodSelection) {
std::cout << "Invalid Option , Try again" << '\n';
std::cin.clear(); std::cin.ignore();
}
}
return selection;
}
void enterSPlayerData(std::vector<sPlayer>& sp)
{
// Ask, how many players we would like to register
std::cout << "\n\nEnter soccer player data\n\nHow many player do you want to register: ";
size_t numberOfPlayersToRegister{ 0 };
std::cin >> numberOfPlayersToRegister;
// Make space in vector for all the players
sp.clear();
sp.resize(numberOfPlayersToRegister);
// Read all players
for (size_t i = 0; i < numberOfPlayersToRegister; ++i) {
std::cout << '\n' << (i+1) <<" Enter --> Last Name --> First Name --> Birt Month --> Birth Day --> Birth Year\n";
std::cin >> sp[i];
}
}
int main()
{
// This is our player vector
std::vector<sPlayer> players{};
// Andf here a copy with the sorted data
std::vector<sPlayer> playersSorted{};
// If we want zo search a name in the vector
std::string searchString{};
bool playerFound{ false };
// Menu selection
int selection{ CmdExit };
do {
selection = getMenuSelection();
switch (selection)
{
case CmdInputData:
// Read player vector
enterSPlayerData(players);
break;
case CmdDisplayOriginalData:
// Show all players
std::cout << "\n\nPlayer List\n\n";
std::copy(players.begin(), players.end(), std::ostream_iterator<sPlayer>(std::cout, "\n"));
break;
case CmdSortByLastName:
// Copy player list and sort the copy
playersSorted.clear();
std::copy(players.begin(), players.end(), std::back_inserter(playersSorted));
std::sort(playersSorted.begin(), playersSorted.end(),
[](const sPlayer & sp1, const sPlayer & sp2) { return sp1.lname < sp2.lname; });
break;
case CmdDisplaySortedData:
// Show the sorted data
std::cout << "\n\nPlayer List Sorted\n\n";
std::copy(playersSorted.begin(), playersSorted.end(), std::ostream_iterator<sPlayer>(std::cout, "\n"));
break;
case CmdSearchLastName:
// Sear for a part of a name
std::cout << "\n\nSearch Player name\n\nEnter some starting characters of Name: ";
std::cin >> searchString;
playerFound = false;
std::for_each(players.begin(), players.end(),
[&searchString, &playerFound](const sPlayer & sp) {
if (sp.lname.find(searchString) != std::string::npos) {
std::cout << "Found Player\n" << sp << '\n';
playerFound = true;
}
}
);
if (!playerFound) std::cout << "\nNo player found\n\n";
break;
default:
selection = CmdExit;
break;
}
} while (selection != CmdExit);
return 0;
}