Question

尝试运行我的代码以查看我是否对自己的分配有任何权利，但是在尝试编译该代码时始终收到错误消息，代码如下。如果有人意识到我什至没有正确执行代码的某些部分，请告诉我，因为我不太确定。

当我尝试在Xcode上编译时，我得到的错误是

“ / clang：-1：链接器命令失败，退出代码为1（使用-v查看调用）”

#include <iostream>
#include <fstream>
#include <string.h>
using namespace std;

// the format of each of the elements in the database
struct OpAmps {
char Name[20]; // the name of the op-amp (e.g. "741")
unsigned int PinCount; // the number of pins in the package
double SlewRate; // the slew rate in volts per microsecond
};

// the length of the fixed array to be used for database - must be at least one
// and no greater the maximum value allowed in an unsigned long (see the file
// limits.h).
#define DATABASE_MAX 10

// file used for the database
#define DATABASE_FILENAME "database.txt"

// function prototypes

void Enter ( OpAmps& OpAmp , unsigned long& length);
void Save ( OpAmps DB[], unsigned long length);
void Load (OpAmps DB[], unsigned long length);
void Display ( OpAmps DB[], unsigned long length);

// Control the entering, saving, loading, sorting and displaying of elements in the
// database.
// Arguments: None
// Returns: 0 on completion
int main()
{
OpAmps OpAmp[DATABASE_MAX];   // the database
unsigned long database_length = 0;  // the number of elements in the database
char UserInput;

// loop until the user wishes to exit
while (1) {

    // show the menu of options
    cout << endl;
    cout << "Op-amp database menu" << endl;
    cout << "--------------------" << endl;
    cout << "1. Enter a new op-amp into the database" << endl;
    cout << "2. Save the database to disk" << endl;
    cout << "3. Load the database from disk" << endl;
    cout << "4. Sort the database" << endl;
    cout << "5. Display the database" << endl;
    cout << "6. Exit from the program" << endl << endl;

    // get the user's choice
    cout << "Enter your option: ";
    cin >> UserInput;
    cout << endl;

    // act on the user's input
    switch(UserInput) {
        case '1':
            Enter(OpAmp[database_length], database_length);
            break;

        case '2':
            Save(OpAmp, database_length);
            break;

        case '3':
            Load(OpAmp, database_length);
            break;

       /* case '4':
            Sort(OpAmp, database_length);
            break;
       */
        case '5':
            Display(OpAmp, database_length);
            break;

        case '6':
            return 0;

        default:
            cout << "Invalid entry" << endl << endl;
            break;
    }
  }
}


// Allow the user to enter a new element into the database. Note that the data is
// simply added to the end the database (if not full) and no sorting is carried
// out.
// Arguments:
//   (1) the element in the database to be entered
//   (2) the position of the element in the database
// Returns: void
void Enter ( OpAmps& OpAmp , unsigned long& length)
{
    // if the database is full, inform the user
if (length >= DATABASE_MAX )
{
    cout << "Database is full." << endl;
}

// if the database is not full, get the data from the user and alter the database
// length
else
{
    cout << "Enter OpAmp Name: ";
    cin >> OpAmp.Name;
    cout << "Enter Pin Count: ";
    cin >> OpAmp.PinCount;
    cout << "Enter Slew Rate: ";
    cin >> OpAmp.SlewRate;

    length++;
   }
}


// Save the database to the file specified by DATABASE_FILENAME. If the file
// exists it is simply overwritten without asking the user.
// Arguments:
//   (1) the database
//   (2) the length of the database
// Returns: void
void Save (OpAmps DB[], unsigned long length)

{
fstream output_file;  // file stream for output

// open the file
output_file.open(DATABASE_FILENAME, ios::out);

if (!output_file.good()) {cout <<"Error"; exit(1);}

// write length information to file
output_file << length << endl;

// write data to file
for (int i = 0; i < length; i++)
{
    output_file << DB[i].Name << DB[i].PinCount << DB[i].SlewRate;

}

// close the file
output_file.close();
}


// Load the database from the file specified by DATABASE_FILENAME. If the file
// exists it simply overwrites the data currently in memory without asking
// the user.
// Arguments:
//   (1) the database
//   (2) the length of the database
// Returns: void
void Load (OpAmps DB[], unsigned long length)
{
fstream input_file;  // file stream for input

// open the file
input_file.open(DATABASE_FILENAME, ios::in);

if (!input_file.good()) {cout <<"Error"; exit(1);}

// load database length information from file
for (int i = 0; i < length; i++)
{
    input_file >> length;
}

// load data from file
for (int i = 0; i < length; i++)
{
    input_file >> DB[i].Name >> DB[i].PinCount >> DB[i].SlewRate;
}

// close the file
input_file.close();
}

C ++ Xcode编译问题：“ / clang：-1：链接器命令失败，退出代码为1（使用-v查看调用）”

0 个答案: