我无法使用类中的这些指针变量在文件上写入数据。程序没有错误,但没有数据写入文件。
请有人告诉我我哪里做错了。
#include <iostream.h>
#include <fstream.h>
class studentinfo
{
private:/*Creating Private Data Members */
char* VUID;
char* campusID;
char* Studentname;
char* Fathername;
public:
void Storefile();/* Function to Store Data in the File*/
char Display();/*Function to Read and then Display Data from the File*/
studentinfo(char*, char*, char*, char*);/*Constructor to initialize Data Members*/
~studentinfo();
};
/* Constructor Defined Here*/
studentinfo::studentinfo(char* VUID, char* campusID, char* Studentname, char* Fathername)
{
cout << "Parameterized Contructor is Called" << endl << endl;
}
/*Destructor Defined Here*/
studentinfo::~studentinfo()
{
cout << "Destructor Called for destruction of the object" << endl;
system("pause");
}
/*Function to Store Data in the File Defined here*/
void studentinfo::Storefile()
{
ofstream re;
re.open("record.txt");
if(!re)/*Error Checking Mechanism*/
{
cout<<"Error Reading File"<<endl;
}
re << VUID << endl << campusID << endl << Studentname << endl << Fathername << endl;/*Using data members to Store data in the File*/
cout << "All the Data Members are Stored in a File" << endl << endl;
re.close();
}
/*Function to Read and then Display the data in the File is definde here */
char studentinfo::Display()
{
char output[100];/*Array to store and display the data*/
ifstream reh;
reh.open("record.txt");
if(!reh)
{
cout << "Error Reading File" << endl;
}
cout << "Following is My Data" << endl << endl;
while(!reh.eof()){
reh.getline(output, 100, '\n');/*Reading the data and storing it in the 'output' array line by line*/
cout << output << endl;
}
reh.close();
}
/*Main Function starting here*/
main()
{
studentinfo s1("mc130202398", "PMTN08", "Rehan Shahzad Siddiqui","Rizwan Ali Siddiqui");/*Object Created and Initialized by constructor calling*/
s1.Storefile();/*Function Call*/
s1.Display();/*Function Call*/
system("pause");
}
您的构造函数已损坏并且所有指针均未分配。在为变量赋值之前,您不能使用它的值。
另外,您使用的是什么蹩脚的编译器或者您有什么警告设置?您的构造函数正在传递指向常量的指针,但它需要非常量指针。那应该确实引起了警告,指出您对这些指针的处理不当。
studentinfo s1("mc130202398", "PMTN08", "Rehan Shahzad Siddiqui","Rizwan Ali Siddiqui");/*Object Created and Initialized by constructor calling*/
请注意,您向构造函数传递了一堆常量。
studentinfo::studentinfo(char* VUID, char* campusID, char* Studentname, char* Fathername)
哎呀,但是构造函数需要常规的char*
指针。那么这些指针应该指向什么呢?
提示:使用合理的 C++ 类,例如std::string
这些问题就会神奇地消失。
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