Thread: Structs:

This is a homework assignment but I am doing a little extra. Mainly because I like to call functions in main and keep it as clear as I can. With that being said, I am having an issue passing input from a struct from one function to another. Also the array is failing but when I did the same thing in initially when I first declared it it was fine, why?

Code:

 #include <iostream>

using namespace std;

void HW_step1and3();
void HW_step_4();
void print_HW4();

const char name_size = 20;

struct StudentRecord {
    char Name[name_size];
    int ID;
    float GPA;
};

void HW_step1and3()
{
    StudentRecord TESCStudent;
    
    TESCStudent.Name[name_size]= {"SuperProgrammer"};  //When I used it in the struct itself it was fine. Now I get an error
    TESCStudent.ID=1234;
    TESCStudent.GPA=4.0;
    
    for (size_t i=0; i<sizeof(TESCStudent.Name); i++) {
         
        cout<< TESCStudent.Name[i];
        
    }
            cout<<"\n" <<TESCStudent.ID<<endl;
            cout<< TESCStudent.GPA<<endl;
            cout<<" "<<endl;
}

void HW_step_4()
{
    StudentRecord TESCStudent;

    cout<<"Please enter the Students Name:"<<endl;
    cin>>TESCStudent.Name;
    
    cout<<"Please Enter the Students ID Number:"<<endl;
    cin>>TESCStudent.ID;
    
    cout<<"Please Enter the students GPA"<<endl;
    cin>>TESCStudent.GPA;
    
    print_HW4(struct TESCStudent.name,struct TESCStudent.ID,struct TESCStudent.GPA);
}

void print_HW4(struct char, struct int, struct float)  // this was a real reach, I have good feeling its wrong
{
    
    //I'll print the above here

}

int main(int argc, const char * argv[])
{
    HW_step1and3();
    
    HW_step_4();
    
    return 0;
}

The instance of TESCStudent in HW_step1and3 is a different instance than the one in HW_step_4. You should declare a single instance of TESCStudent in main, and then pass a pointer to TESCStudent as a parameter to the functions that main calls. Structs with a basic type, like "struct char" are not allowed. Just use char, int, float, or pass a pointer to TESCStudent as a parameter to print_HW4.

Thank you for the help guys. I would love to use stings and simply getline but I was told i had to use an array. I even e-mailed him and he told me to "Follow the assignment instructions".

Ok, so I go the programing working but I wanted to use the new c++11 array format and not

Code:

cout<<"Please enter the Students Name:"<<endl; cin>>TESCStudent.Name;

is failing.

I am going to clean this code up and put it all in functions. I just wanted to get it to work and from there break it down since it is such a small program. I think it would look a lot neater if I used functions.

Code:

#include <iostream>
#include <array>
using namespace std;

void HW_step1and3();
void HW_step_4();
void print_HW4();

const size_t name_size = 20;

struct StudentRecord {
    array<char, name_size> Name = {"SuperProgrammer"};
    int ID=1234;
    float GPA=4.0;
}TESCStudent;


int main(int argc, const char * argv[])
{
    
    for (char student: TESCStudent.Name) {
    cout<< student;
    }

    cout<<"\n" <<TESCStudent.ID<<endl;
    cout<< TESCStudent.GPA<<endl;
    cout<<" "<<endl;
    
    
    cout<<"Please enter the Students Name:"<<endl;
    cin>>TESCStudent.Name;                           //failing
    
    cout<<"Please Enter the Students ID Number:"<<endl;
    cin>>TESCStudent.ID;
    
    cout<<"Please Enter the students GPA"<<endl;
    cin>>TESCStudent.GPA;
    
    
    for (char student: TESCStudent.Name) {
        cout<< student;
    }
    
    cout<<"\n" <<TESCStudent.ID<<endl;
    cout<< TESCStudent.GPA<<endl;
    cout<<" "<<endl;


    return 0;

}

Think I figured it out but I am back to having issues with HW_task4 when I call it in HW_task3. I do not have to use functions but since I ran into this issue I really would like to figure out what the heck the deal is.

Code:

 #include <iostream>
#include <array>
using namespace std;

void HW_task2();
void HW_task3();
void HW_task4();

const size_t name_size = 20;

struct StudentRecord {
    array< char, name_size> Name = {"SuperProgrammer"};
    int ID=1234;
    float GPA=4.0;
}TESCStudent;

void HW_task2()
{

    for (char student: TESCStudent.Name) {
        cout<< student;
    }
    
    cout<<"\n" <<TESCStudent.ID<<endl;
    cout<< TESCStudent.GPA<<endl;
    cout<<" "<<endl;


}

void HW_task3()
{

    cout<<"Please enter the Students Name:"<<endl;
    cin>>(TESCStudent.Name[name_size]);
    
    cout<<"Please Enter the Students ID Number:"<<endl;
    cin>>TESCStudent.ID;
    
    cout<<"Please Enter the students GPA"<<endl;
    cin>>TESCStudent.GPA;
    
    HW_task4(TESCStudent.Name[name_size],TESCStudent.ID,TESCStudent.GPA);
   

}

void HW_task4(char,int,float)
{
    for (char student: TESCStudent.Name) {
        cout<< student;
    }
    
    cout<<"\n" <<TESCStudent.ID<<endl;
    cout<< TESCStudent.GPA<<endl;
    cout<<" "<<endl;

}

int main(int argc, const char * argv[])
{
    
    HW_task2();
    
    HW_task3();
    
    HW_task4();
   


    return 0;

}

Your function call, function implementation and function prototype must all agree as to the number and type of parameters.

Also you need to add some variable names to your function implementation.

Why are you using std::array for C-strings? The std::array class is not suited for use with C-strings.

Do you know the difference between a char and an array of char?

Do you realize that the following is trying to retrieve one single character into your array, not a string. And that you are accessing your array out of bounds. Arrays in C/C++ start at zero and stop at size - 1. You're trying to access array[size] which is out of bounds.

Finally why the global variable (TESCStudent)? You need to learn to properly pass local variables to and from your functions as required.

Jim

I dont want to use an array but I was told to. I have to use TESCStudent so I figured I would put it global so I didn't have to keep writing it.

Out of bounds? You mean if I put in more then one letter and a name?

A single Character is just that a single character like 'c' and an array can hold variables of any kind in address or locations like PO box would.

I have everything working but the array.

Code:

 void HW_task1()
{
    TESCStudent.Name[SIZE] = {'S','u','p','e','r','P','r','o','g','r','a','m','m','e','r'};
    TESCStudent.ID=1234;
    TESCStudent.GPA=4.0;
    
    for (int i=0; i<SIZE; i++) {
        
        cout<<TESCStudent.Name[i];
    }
    cout<<"\n" <<TESCStudent.ID<<endl;
    cout<< TESCStudent.GPA<<endl;
    cout<<" "<<endl;


}

Pretty messy huh?

Very!

What's wrong with something like:

Code:

   char array[name_size] = "SuperProgrammer";

Jim

Jim I tired that but it failed. This is what I have now and I feel pretty solid about it. What do you guys think?

Once again thank you very much. I seem to learn more on this site then I do in my class.

Code:

 #include <iostream>
#include <string>

#define SIZE 20
using namespace std;

void HW_task2();
void HW_task3();



struct StudentRecord {
    char Name[SIZE];
    int ID;
    float GPA;
}TESCStudent;

void HW_task1_2()
{
    char str1[]="Super Programer";
    
	strcpy(TESCStudent.Name,str1);
    cout<<"Students Name: ";
    for (int i=0; i<sizeof(str1)-1; i++) {
        
        cout<<TESCStudent.Name[i];
    }
    
    TESCStudent.ID=1234;
    TESCStudent.GPA=4.0;
    
    cout<<"\nStudents ID: " <<TESCStudent.ID<<endl;
    cout<<"Students GPA "<<TESCStudent.GPA<<endl;
    cout<<" "<<endl;
    
    
}

void HW_task3_4()
{
    for(int i=0;i<SIZE;i++)
        TESCStudent.Name[i]='\0';
    
    cout<<"Please enter the Students Name:"<<endl;
    cin.getline(TESCStudent.Name,20,'\n');
    
    cout<<"Please Enter the Students ID Number:"<<endl;
    cin>>TESCStudent.ID;
    
    cout<<"Please Enter the students GPA"<<endl;
    cin>>TESCStudent.GPA;
    
    cout<<"Students Name ";
	for (int i=0;i<sizeof(TESCStudent.Name);i++)
	{
  cout<<TESCStudent.Name[i];
	}
    
    cout<<"\nStudents ID: " <<TESCStudent.ID<<endl;
    cout<<"GPA: "<<TESCStudent.GPA<<endl;
    cout<<" "<<endl;
    
}


int main(int argc, const char * argv[])
{
    
    HW_task1_2();
    
    HW_task3_4();
    
    return 0;
    
}