在为我的小堂兄进行这个项目时，我遇到了许多困难。我想知道是否有人可以帮助我使用char输出完整的句子（或帮助我修复这些错误。）我是一个相对较新的程序员（大约8个月）。这是我的代码/我尝试过的。一旦插补了一个句子，或者打开文件后没有响应，大多数错误都会导致程序冻结。
#include<iostream>
#include<fstream>
#include<cctype>
#include<iomanip>
class legoset
{
char setcatname[25];
char name[50];
char legoinclude[25];
char legotype[25];
public:
void create_category();
void show_category() const;
void modify();
void report() const;
int retacno() const;
};
void legoset::create_category()
{
std::cout << "Please enter a category name : \n";
std::cin >> setcatname;
//std::cin.getline(setcatname, 25);
std::cout << "Please enter your username! \n";
std::cin >> name;
std::cin.ignore();
std::cin.getline(name, 50);
std::cout << name << " , is it a vehicle or building (V/B)?\n";
std::cin >> legotype;
legotype[25] = toupper(legotype[25]);
std::cin.getline(legotype, 25);
std::cout << "\n Please enter the name of the lego set. \n";
std::cin >> legoinclude;
//std::cin.getline(legoinclude, 25);
std::cout << "\n\n Category Created Successfully!!!";
return;
}
void legoset::show_category() const
{
std::cout << "Category : \n" << setcatname;
std::cout << "Username Of Holder \n: " << name;
std::cout << " Lego type (B/V) : " << legotype;
std::cout << " Lego set (with details) : " << legoinclude;
return;
}
void legoset::modify()
{
std::cout << "Category : \n" << setcatname[25];
std::cout << "\nModify Holder's name : ";
std::cin.ignore();
std::cin.getline(name, 50);
std::cout << "\nModify A Building or vehicle class ( B/V ) : ";
std::cin >> legotype[25];
legotype[25] = toupper(legotype[25]);
std::cout << "\nModify Lego set (with details) : ";
std::cin >> legoinclude[25];
}
void legoset::report() const
{
std::cout << setcatname[25] << std::setw(10) << " " << name << std::setw(10) << " " << legotype[25] << std::setw(6) << legoinclude[25] << std::endl;
}
int legoset::retacno() const
{
return setcatname[25];
}
void write_legoset(); //function to write record in binary file
void display_sp(int); //function to display account details given by user
void modify_set(int); //function to modify record of file
void delete_set(int); //function to delete record of file
void display_all(); //function to display all account details
void intro(); //introductory screen function
int main()
{
char choice;
int num;
intro();
do
{
system("cls");
std::cout << "\n\n\n\tMAIN MENU";
std::cout << "\n\n\t01. New Category";
std::cout << "\n\n\t02. ADD A NEW SET";
std::cout << "\n\n\t03. ALL USERS HOLDER LIST";
std::cout << "\n\n\t04. DELETE A CATEGORY";
std::cout << "\n\n\t05. MODIFY A CATEGORY";
std::cout << "\n\n\t06. EXIT";
std::cout << "\n\n\tSelect Your Option (1-6) ";
std::cin >> choice;
system("cls");
switch (choice)
{
case '1':
write_legoset();
break;
case '2':
std::cout << "\n\n\tEnter The category Name : "; std::cin >> num;
display_sp(num);
break;
case '3':
display_all();
break;
case '4':
std::cout << "\n\n\tEnter The Category Name : "; std::cin >> num;
delete_set(num);
break;
case '5':
std::cout << "\n\n\tEnter The Category Name : "; std::cin >> num;
modify_set(num);
break;
case '6':
std::cout << "\n\n\tThanks for using lego managemnt system!";
std::exit;
break;
default: std::cout << "\a";
}
std::cin.ignore();
std::cin.get();
} while (choice != '6');
return 0;
}
//***************************************************************
// function to write in file
//****************************************************************
void write_legoset()
{
legoset lego;
std::ofstream outFile;
outFile.open("legoset.dat", std::ios::binary | std::ios::app);
lego.create_category();
outFile.write(reinterpret_cast<char *> (&lego), sizeof(legoset));
outFile.close();
}
//***************************************************************
// function to read specific record from file
//****************************************************************
void display_sp(int n)
{
legoset lego;
bool flag = false;
std::ifstream inFile;
inFile.open("legoset.dat", std::ios::binary);
if (!inFile)
{
std::cout << "File could not be open !! Press any Key...";
return;
}
std::cout << "\nLEGOSET DETAILS\n";
while (inFile.read(reinterpret_cast<char *> (&lego), sizeof(legoset)))
{
if (lego.retacno() == n)
{
lego.show_category();
flag = true;
}
}
inFile.close();
if (flag == false)
std::cout << "\n\nLego set does not exist in this file";
}
//***************************************************************
// function to modify record of file
//****************************************************************
void modify_set(int n)
{
bool found = false;
legoset lego;
std::fstream File;
File.open("legoset.dat", std::ios::binary | std::ios::in | std::ios::out);
if (!File)
{
std::cout << "File could not be open !! Press any Key...";
return;
}
while (!File.eof() && found == false)
{
File.read(reinterpret_cast<char *> (&lego), sizeof(legoset));
if (lego.retacno() == n)
{
lego.show_category();
std::cout << "\n\nPlease Enter The New Details For This Category." << std::endl;
lego.modify();
int pos = (-1)*static_cast<int>(sizeof(legoset));
File.seekp(pos, std::ios::cur);
File.write(reinterpret_cast<char *> (&lego), sizeof(legoset));
std::cout << "\n\n\t Category Updated!";
found = true;
}
}
File.close();
if (found == false)
std::cout << "\n\n Category Not Found ";
}
//***************************************************************
// function to delete record of file
//****************************************************************
void delete_set(int n)
{
legoset lego;
std::ifstream inFile;
std::ofstream outFile;
inFile.open("legoset.dat", std::ios::binary);
if (!inFile)
{
std::cout << "File could not be open !! Press any Key...";
return;
}
outFile.open("Temp.dat", std::ios::binary);
inFile.seekg(0, std::ios::beg);
while (inFile.read(reinterpret_cast<char *> (&lego), sizeof(legoset)))
{
if (lego.retacno() != n)
{
outFile.write(reinterpret_cast<char *> (&lego), sizeof(legoset));
}
}
inFile.close();
outFile.close();
remove("legoset.dat");
rename("Temp.dat", "legoset.dat");
std::cout << "\n\n\tCategory Deleted ..";
}
//***************************************************************
// function to display all accounts deposit list
//****************************************************************
void display_all()
{
legoset lego;
std::ifstream inFile;
inFile.open("legoset.dat", std::ios::binary);
if (!inFile)
{
std::cout << "File could not be open !! Press any Key...";
return;
}
std::cout << "\n\n\t\tUSER HOLDER LIST\n\n";
std::cout << "====================================================\n";
std::cout << "A/c no. NAME Type Balance\n";
std::cout << "====================================================\n";
while (inFile.read(reinterpret_cast<char *> (&lego), sizeof(legoset)))
{
lego.report();
}
inFile.close();
}
void intro()
{
std::cout << "\n\n\n\t LEGOSET";
std::cout << "\n\n\tMANAGEMENT";
std::cout << "\n\n\t SYSTEM";
std::cout << "\n\n\n\nMADE BY : Philippe Barry";
std::cin.get();
}
//***************************************************************
// END OF PROJECT
//***************************************************************
答案 0 :(得分：1)
请注意，C ++中的数组索引比数组大小小0到1。因此，索引0是第一个元素，索引1是第二个元素，依此类推。因此，如果将一个char数组声明为大小25，则访问索引25会超出数组的末尾，并导致未定义的行为-您的程序可能会崩溃，冻结或发生其他任何事情。另外，访问索引24只会给您每个字符串后面的“空字符”。如果您确定输入的字符长度为24个字符（不应输入），则索引23将包含最后一个字符。
无论如何，您实际上不应该在C ++中使用静态长度char数组。当输入字符串大于数组大小时，即使当前的代码大部分时间都可以在char数组中使用，您当前的代码也会失败。用std :: string替换所有char数组的类型，输入函数应该起作用。
此外，正如Sam Varsavchik所说，不要立即编写整个程序。这使其成为调试的噩梦。分块编写代码-首先编写输入函数，然后是调试函数，该函数打印出所有成员变量的值。首先调试该位，然后继续其余部分。