I enter info about the student first name lastname index number and degree for each subject.If the degree is over 5 the subject is passed and i get average from passed subjects.If i print the function like printf("%f",P.averagefunc()) the number is ok but i when i try to get the average to variable like float average=P.averagefunc(); inside struct student or float average=averagefunc(); inside struct subject and i print the result i get some weird number like -888266.00000.Any help how i can get the float function to float variable?
Please dont downvote the question i am new to this and i tried to explain my problem as best as i could.
struct subject{
int programming;
int electronics;
int calculus1;
int english;
int usersoftware;
float averagefunc()
{
int sum=0;
int passed=0;
if(programming>5)
{
sum+=programming;
passed++;
}
if(electronics>5)
{
sum+=electronics;
passed++;
}
if(calculus1>5)
{
sum+=calculus1;
passed++;
}
if(english>5)
{
sum+=english;
passed++;
}
if(usersoftware>5)
{
sum+=usersoftware;
passed++;
}
return (float)suma/(float)polozeni;
}
};
struct student{
char firstname[10];
char lastname[15];
int indexnumber;
struct subject P;
};
Related
#include<iostream>
#include<string>
using namespace std;
class customerNode{
public:
int c_id;
int quantity;
string c_name;
string type;
customerNode* next_node;
};
class Queue{
public:
customerNode* front=NULL;
customerNode* rear=NULL;
int getc_id();
string getc_name();
int getquantity();
int setc_id(int c_id);
string setc_name(string c_name);
int setquantity(int quantity);
void display();
void enqueue(int c_id,int quantity,string c_name);
void dequeue();
int nor_queue,exp_queue;
};
int Queue::getc_id(){
int c_id;
cout<<"enter customer id:"<<endl;
cin>>c_id;
return c_id;
}
int Queue::getquantity(){
int quantity;
cout<<"enter quantity customer purchased:"<<endl;
cin>>quantity;
return quantity;
}
string Queue::getc_name(){
string c_name;
cout<<"enter customer name:"<<endl;
cin>>c_name;
return c_name;
}
int Queue::setc_id(int c_id){
return c_id;
}
int Queue::setquantity(int quantity){
return quantity;
}
string Queue::setc_name(string c_name){
return c_name;
}
void Queue:: enqueue(int c_id,int quantity,string c_name){
int exp_queue,nor_queue;
cout<<"enter customer information"<<endl;
customerNode* new_node=new customerNode;
new_node->c_id=c_id;
new_node->c_name=c_name;
new_node->quantity=quantity;
new_node->next_node=NULL;
if(front==NULL){
rear=front;
rear=new_node;
rear->next_node=NULL;
}
else{
while(rear->next_node!=NULL)
rear=rear->next_node;}
rear->next_node=new_node;
rear=new_node;
if(new_node->quantity<=5)
{
new_node->type="express";
exp_queue++;
cout<<"customer entered in express queue"<<endl;
cout<<"total customer in express queue="<<exp_queue<<endl;
}
else{
new_node->type="normal";
nor_queue++;
cout<<"customer entered in normal queue"<<endl;
cout<<"total customer in normal queue="<<nor_queue<<endl;
}
}
void Queue::display(){
customerNode* ptr=front;
cout<<"normal queue customer information"<<endl;
while(ptr!=NULL)
{
if(ptr->type=="normal"){
cout<<"custumer name:"<<setc_name(ptr->c_name)<<endl;
cout<<"custumer id:"<<setc_id(ptr->c_id)<<endl;
cout<<"item puchased by custumer :"<<setquantity(ptr->quantity)<<endl;
nor_queue--;
cout<<"total customer in normal queue:"<<nor_queue<<endl;
}
ptr=ptr->next_node;
}
cout<<"express queue customer information"<<endl;
while(ptr!=NULL)
{
if(ptr->type=="normal"){
cout<<"custumer name:"<<setc_name(ptr->c_name)<<endl;
cout<<"custumer id:"<<setc_id(ptr->c_id)<<endl;
cout<<"item puchased by custumer :"<<setquantity(ptr->quantity)<<endl;
nor_queue--;
cout<<"total customer in normal queue:"<<exp_queue<<endl;
}
}
}
main(){
Queue q;
char i;
do{
q.enqueue(c_id,quantity,c_name );
cout<<"do you want to enter another customer?input y or Y for yes and n or N for no:";
cin>>i;
}
while(i=='y'||i=='Y');
q.display();
return(0);
};`
in mian fuction i m getting error c_id,quantity,c_name is not declare before,when i use int c_id,int quantity,string c_name than it shows expected primary expression befor int and strinng..i dont know which expression is missing or how to resolve the error,
please help me to solve this i hve to submit assing as soon as possible.
A much simpler example with similar error is:
#include <iostream>
struct foo {
int x = 0;
int y = 0;
void assign(int a, int b){
x = a;
y = b;
}
};
int main()
{
foo f;
f.assign(x,y);
}
The error is:
<source>: In function 'int main()':
<source>:14:14: error: 'x' was not declared in this scope
14 | f.assign(x,y);
| ^
<source>:14:16: error: 'y' was not declared in this scope
14 | f.assign(x,y);
| ^
x and y are declared in the scope of the class. Instances of foo have members of that name. To access those members you would write f.x or f.y.
c_id,quantity, and c_name are not declared in your main. I am not eniterly sure what you want to do and it is too much code to adress all its issues. Though, if you want to declare variables of that name in main then you need to do that:
int main(){ // main must return int
Queue q;
char i;
int c_id = 42;
int quantity = 0;
string c_name{"some fancy name"};
q.enqueue(c_id,quantity,c_name );
// ...
}
It is a little surprising that you write code with advanced stuff like pointers, classes and what not, but don't know about scope. Try to search for "scope" and read about it.
There are more issues in your code. For example int Queue::setquantity(int quantity){ return quantity;} does not set anything. Though, as I wrote before, this is just way too much code to adress all of them. I can only advise you to start with less code and only write more when you know the code you have already does compile and passes your tests. And thats not just an advise for a beginner, but anybody is making mistakes and you rather want to fix one problem then many at the same time.
Problem is, on execution, the value of roundCost I'm getting is
something like -1220673834. I post the entire program because I'm not
sure where I'm going wrong.
Note: I was asked to take all variables as double type and later,
roundCost should be of type int. So I used type conversion there.
#include<iostream>
using namespace std;
class Restaurant{
private:
double tip, tax,totalCost,mealCost, tipPercent, taxPercent;
int roundCost;
public:
int tipCalc(double)
{
tip=mealCost*(tipPercent/100);
return tip;
}
int taxCalc(double)
{
tax=mealCost*(taxPercent/100);
return tax;
}
int totalCost1()
{
totalCost=mealCost+tip+tax;
return totalCost;
}
int roundCost1(double)
{
roundCost=(int)totalCost;
return roundCost;
}
}; // class ends
int main()
{
double mealCost, tipPercent, taxPercent, totalCost;
int roundCost;
Restaurant ob1;
cout<<"\n Enter mealCost \n";
cin>>mealCost;
cout<<"\n Enter mealtipPercent \n";
cin>>tipPercent;
cout<<"\n Enter mealtaxPercent \n";
cin>>taxPercent;
ob1.tipCalc(tipPercent);
ob1.taxCalc(taxPercent);
ob1.totalCost1();
ob1.roundCost1(totalCost);
cout<<"\n Round of cost is "<<roundCost<<endl;
return 0;
}
One thing you seem to be missing is that variables in your class have a different scope then variables in your main. You set the mealcost in your main from cin but you never passed this variable to the class. I changed this to be done using a constructor that sets the meal cost on creation. In every class you make you should always add a constructor. Also, you should be naming the variables your passing to functions and then using the same name in the function. For example in the tax percent function i pass double t, t is the percent, we then use t in the calculation. Your round cost variable was also private so you needed to output it via a function.
Also int functions will return a value, if you are using this type of function you should be assigning the return variable to something, but since you are just setting things in your class you can use void functions for most. The only time you use a value in the main is in the roundcost so this one is good to have it return a value. As it is int (which i assumed you wanted) it will get no decimal points and it will simply cut off any decimals in the total cost (ie 75.75 would become 75).
#include<iostream>
using namespace std;
class Restaurant{
private:
double tip, tax,totalCost,mealCost;
int roundCost;
public:
Restaurant (double m)
{
mealCost = m;
}
void tipCalc(double t)
{
tip=mealCost*(t/100.0);
}
void taxCalc(double t)
{
tax=mealCost*(t/100.0);
}
void totalCost1()
{
totalCost=mealCost+tip+tax;
}
int roundCost1()
{
roundCost=(int)totalCost;
return roundCost;
}
}; // class ends
int main()
{
double mealCost, tipPercent, taxPercent, totalCost;
int roundCost;
cout<<"\n Enter mealCost \n";
cin>>mealCost;
Restaurant ob1(mealCost);
cout<<"\n Enter mealtipPercent \n";
cin>>tipPercent;
cout<<"\n Enter mealtaxPercent \n";
cin>>taxPercent;
ob1.tipCalc(tipPercent);
ob1.taxCalc(taxPercent);
ob1.totalCost1();
cout<<"\n Round of cost is "<<ob1.roundCost1()<<endl;
return 0;
}
Try to do a bit more research next time by using a debugger, outputting cout statements regularly and searching for the errors you find but this will give you a working code this time.
I have the following student class with two similar function-
One is static and one is not.
class Student
{
public:
Student(std::string name_ , int const id_);
virtual ~Student();
void addGrade(int const grade2add);//grade above 100
void removeGrade (int const grade2remove); //update maxGrade
void print(); //id, name, grades
int getStudentMaxGrade();
static int getMaxGrade();
private:
std::string name; //max 20 chars
int const id; //5 digits, only digits
std::vector<int> grades;
float avg;
static int maxGrade;
};
The static int maxGradeis initialize with 0.
I implement the function:
int Student::maxGrade = 0;
int Student::getStudentMaxGrade()
{
return *max_element(grades.begin(), grades.end());
}
I'm not sure how to implement the static function.
I tried:
int Student::getMaxGrade()
{
maxGrade= *max_element(grades.begin(), grades.end());
return maxGrade;
}
But it doesn't work (doesn't compile)
The way you have your data laid out, each student knows nothing about the grades of the other students, and the class knows nothing about the grades of any particular student. This is good encapsulation, but in order to retrieve the maximum grade of all students, you have to include a bit of logic to keep track of the maximum grade that has been input. Something like this:
void Student::addGrade (int const grade) {
// do the stuff, add the grade
if (grade > maxGrade) // Check if the grade is higher than the previous
maxGrade = grade; // highest recorded grade and, if so, overwrite it.
}
This way, every time a higher grade is input, it becomes the new highest grade, and in that way the class always knows the highest grade without having to keep track of each and every student's grades.
So I've to do another exercise. This time I need to define a struct and a 100-elements array, which will store information about the book (title, author, ID number, price) and a simple function which will print info about all of the books stored. I started with that code:
#include <iostream>
using namespace std;
int main()
{
struct name_surname {string name, surname;};
struct book {string title; name_surname author_name, author_surname; int ID; int price;};
return 0;
}
And, well, what now? How can I store this in an array?
You just create an array of type book or name_surname or whatever you want.
Example:
book arr[100];
arr[0].title = "The last robot";
arr[0].ID = 2753;
Tips:
It's good programming practice if your structs/classes begin with with capital letter, so it's easier to distinguish them and so it is easier to name the variable the same name just without the capital letter. Example.
struct Name_surname
{
string name, surname;
};
Name_surname name_surname[100];
name_surname[0].name = "MyName";
Another tip is that I'd really suggest you learn how to research, this question has been answered millions of times and answers are all over the internet.
Here is my suggestion :
struct book
{
string title;
string name_surname;
string author_name;
string author_surname;
int ID;
int price;
};
struct Database
{
book *array;
void printDatabase()
{
for(int i = 0 ; i < 100 ;i++)
cout<<array[i].title<<endl;
}
Database()
{
array = new string [100];
}
};
Your name structure seems a little confused but creating an array is simply a case of declaring a variable with [] appended to it giving the size.
For example:
struct full_name
{
std::string firstname;
std::string surname;
};
struct book
{
std::string title;
full_name author;
int ID;
int price;
};
int main()
{
// Declare an array using []
book books[100]; // 100 book objects
// access elements of the array using [n]
// where n = 0 - 99
books[0].ID = 1;
books[0].title = "Learn To Program In 21 years";
books[0].author.firstname = "Idont";
books[0].author.surname = "Getoutalot";
}
What do you think about that:
#include <iostream>
using namespace std;
struct book {string title; string name; int ID; int price;} tab[100];
void input(book[]);
void print(book[]);
int main()
{
input(tab);
print (tab);
return 0;
}
void input(book tab[])
{
for (int i=0;i<3;i++)
{
cout<<"\nBook number: "<<i+1<<endl;
cout<<"title: ";cin>>tab[i].title;
cout<<"name: ";cin>>tab[i].name;
cout<<"ID: ";cin>>tab[i].ID;
cout<<"price: ";cin>>tab[i].price;
}
}
void print (book tab[])
{
for (int i=0; i<3; i++)
{
cout<<"\nBook number: "<<i+1<<endl;
cout<<"title: "<<tab[i].title;
cout<<"\nname: "<<tab[i].name;
cout<<"\nID: "<<tab[i].ID;
cout<<"\nprice: \n"<<tab[i].price;
}
}
I've done this with help from some Yt video. It works, but, is there a way to do it better, or just leave it how it is? And I have a question: Why those function parameters? Can't I just say tab[] or something else?
Computer languages are based on general and recursive rules. Just try to experiment and extrapolate with the basic understanding to build seemingly complex stuff. Coming to what you are trying to achieve:
We know, an array can be declared for any data-type (primitive or derived, one might call them POD and ADT).
We know, struct can comprise of any number of elements of any data-types.
Now, we can see that it is just as natural to say MyStruct[] as it is to int[].
It is better to prefer std::array if using modern compiler.
i was exploring all the possibilities in structures in C++, and when i came to the topic pointers to structure i got stuck with some run time error.
Here is my code:
#include<iostream>
#include<string>
using namespace std;
// globally defined structure can be used in any method
struct stud
{
int roll;
string sname;
// nested structure for date of birth
struct dob
{
int date;
int month;
int year;
} dob1;
int marks1;
int marks2;
int marks3;
} stud1 = {1,"pranshu1",{11,4,1993},65,87,80};
// function to calculate average of a student
float calaverage(stud s1)
{
float savg=s1.marks1+s1.marks2+s1.marks3;
savg=savg/3;
return savg;
}
// function to calculate the average of whole class
// function parameter are the starting address of the array of the structure stud
// and the total no of elements in the array
float avgclass(stud *ptr, int no_of_stud)
{
float classtotal=0;
for(int i=0;i<no_of_stud; i++)
{
classtotal=classtotal+calaverage(*(ptr+i));
}
return classtotal;
}
int main()
{
// array of structure
struct stud class1[3]=
{
stud1,
{2,"pranshu2",{11,4,1993},80,95},
{3,"pranshu3",{11,4,1993},64,84,93}
};
// initializing the value by accessing the member
class1[0].marks3=93;
struct stud* stud5;
stud5->roll=10;
stud5->sname="pranshu";
stud5->dob1.date=11;
stud5->dob1.month=4;
stud5->dob1.year=93;
stud5->marks1=97;
stud5->marks2=45;
stud5->marks3=98;
cout<<stud5->roll<<endl;
// average marks of student 1
cout<<"Average marks of "<<stud1.sname<<" with roll no "<<stud1.roll<<" is "<<calaverage(stud1)<<endl;
// class average
cout<<"Class average is "<<avgclass(class1,3)<<endl;
}
The error was with stud5, but i didnt get any clue about it..
struct stud* stud5; is just a pointer ... you should allocate also memory:
stud5 = new stud;
to have an object.