Having trouble editing a record from a list of students

[rephlex]

Hi, I've been trying to get this function to work(editing a record from a list of students) and I've been having trouble with it.. can someone help me with it, thank you

int Search(Student List[], int Size, string Target)
{
    for(int i = 0 ; i < Size ; i++)
        if (Target == List[i].LastName)
            return i;
    return -1;
}
 
void Edit_Record(Student List[], Student & Temp)
{
    int Index;
    string Target;
    int Size = 0;
 
    cout << "Please enter the student Last Name you want to edit: ";
    cin >> Target;
    Index = Search(List,Size,Target);
    if(Index!=-1){
        cout<<"Procede to change the student's information"<<endl;
 
        cout << "Enter Student" << List[Index].LastName + ", " + List[Index].FirstName << "'s new information" << endl;
        cout << "Enter the new First Name: ";
        cin >> List[Index].FirstName;
        cout << "Enter the new Last Name: ";
        cin >> List[Index].LastName;
        cout << "Enter the new Quiz Score: ";
        cin >> List[Index].Quiz;
            cout << setw(20) <<"Scores for Six Tests:" << endl ;
            for (int j = 0 ; j < 6 ; j++)
            {
                cout <<setw(7)<< " Test # " << j+1 << ": " ;
                cin >> List[Index].Test[j];
 
            }
    }
    else
        cout << "\nThis student information does not exist on the list. Try again.\n";
    List[Index] = Temp;
}
 

[weaknessforcats]

First, this code:

cin >> Target;

limits the last name to one word. If there can be last names of more than one word (weaknessforcats III) then this code will crash the program. You would use cin.getline() instead.

Second, this code:

Index = Search(List,Size,Target);

passes Size to Search. Size is defined as 0 so the Search probably won't look at much.

The thing about arrays is once you pass the array to a function all that passes is the address of the array so that looking from inside the function you see the address but not the number of elements. If you use an array, then you must always pass in the number of elements in addition to the array name.

Third, your Search command should return 0 for success and not-zero for failure. The programming community is used t this. The not-zero allows you to return many values from a function so the nature of the error can be better handles by the calling function.

Fourth, this code:

cin >> Target;

only works if the last name is just a single word. weaknessforcats III would not be allowed.

Read up on cin. Every function using cin, like the operator>> in this case, first checks to see if the stream is in an error state, If it is, then operator>> just returns without doing anything. The effect you see is that things go along and then suddenly every cin>> in the program stops working.

You should have code like:

cin >> Target;
if (cin.fail())
{
     //data entry failed
     //return an error code
}
 

The is also a cin.good() and the one you use is the one that does not require an ! in the code. Like, if (!cin.fail()). Use if (cin.good()) instead.

You can clear the stream failbit by calling cin.clear(). But note that this just resets the failbit and does not fix the data problem that caused the failbit to be set.

I hope some of this helps.