Thread: C++ strings

Hello,

My question is on c++ strings. At the moment my program is reading input in one line at a time after the user presses enter.

I want to read multiple values in on a single line
Example: "apple banana orange end"

How would I do this?

MAIN

Code:

#include "Header.h"
#include "Orange.h"
#include <iostream>
#include <string>
#include <cctype>
using namespace std;

int main()
{
    string s;
    Orange type;
    cout << "<end> to exit program" << endl;
    do
    {
        cout << "\nEnter <banana>, <apple>, or <orange>: ";

            getline(cin, s);
        

        type.Input(s);
        type.Error_message(s);
        type.Fruit_count(s, 0, 0, 0);
        type.End(s);
    
    } while (s != "end");

    cout << "Total Bananas: " << type.total_banana(0) << endl;
    cout << "Total cost of Bananas: $" << type.total_cost_banana(1.20) << endl << endl;

    cout << "Total Apples: " << type.total_apple(0) << endl;
    cout << "Total cost of Apples: $" << type.total_cost_apple(0.50) << endl << endl;

    cout << "Total Oranges: " << type.total_orange(0) << endl;
    cout << "Total cost of Oranges: $" << type.total_cost_orange(0.60) << endl << endl;

    cout << endl;

    system("PAUSE"); 
    return 0;
}

CLASS HEADER

Code:

#pragma once
#include <iostream>
#include <string>
using namespace std;
class Orange
{
private:
    int total_banana_count = 0, total_apple_count = 0, total_orange_count = 0;
    string s;
    string x;
public:
    void Input(string x);
    void Error_message(string s);
    void Fruit_count(string s, int banana_count, int apple_count, int orange_count );
    void End(string s);
    int total_banana(int z);
    double total_cost_banana(double z);
    int total_apple(int y);
    double total_cost_apple(double y);
    int total_orange(int h);
    double total_cost_orange(double h);
};

CLASS CPP

Code:

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

void Orange::Input(string x)
{
    s = x;
}

 
void Orange::Error_message(string s)
{
    if (s != "banana" && s != "apple" && s != "orange" && s != "end")
    {
        cout << "Incorrect entry: " << endl;
         
    }
}

void Orange::Fruit_count(string s, int banana_count, int apple_count, int orange_count)
{

    if (s == "banana")
    {
        total_banana_count++;
        total_banana_count += banana_count;
         
        //return banana_count;
     
    }
    else if (s == "apple")
    {
        total_apple_count++;
        total_apple_count += apple_count;
         
        //return apple_count;
 
    }
    else if (s == "orange")
    {
        orange_count++;
        total_orange_count += orange_count;
         
        //return orange_count;

    }
     
}

void Orange::End(string s)
{
    while (s == "end")
    {
        cout << "\nProgram terminating" << endl;
        break;
    }

}

int Orange::total_banana(int z)
{
    z = total_banana_count;
    return total_banana_count;
}

double Orange::total_cost_banana(double z)
{
    z *= total_banana_count;
     
    return z;
}

int Orange::total_apple(int y)
{
    y = total_apple_count;
    return total_apple_count;
}

double Orange::total_cost_apple(double y)
{
     
    if (total_apple_count % 3 == 0)
    {
            int y = total_apple_count / 3;
            y * 0.5;

            return y;
    }
    else 
    {
        int z = total_apple_count / 3;
            y *= total_apple_count - z;
            return y;
     }
}

int Orange::total_orange(int h)
{
    h = total_orange_count;
    return total_orange_count;
}

double Orange::total_cost_orange(double h)
{
    h *= total_orange_count;
    return h;
}

Originally Posted by immy

cin >> s would store 1 variable (allowing one input). I want to store several variables on the same line: "apple banana orange end"

Have you even bothered to read up on what stream operators do?

"cin >> a >> b" will read values for two variables a and b. "cin >> s" done n times will also read something into s, n times.

Originally Posted by whiteflags

You could literally replace the getline() statement in your code with "cin >> s" and it will work. As I said before, you do not need vector at all. To be fair, you don't need vector in the example either:

Code:

Josh2@Josh-PC /cygdrive/c/users/josh2/desktop
$ ./foo
apple orange banana end
"apple"
"orange"
"banana"
"end"

Josh2@Josh-PC /cygdrive/c/users/josh2/desktop
$ cat foo.cpp
#include <iostream>
#include <string>
using namespace std;

int main()
{
    string s;
    do
    {
        cin>>s;
        cout<<'\"'<<s<<'\"'<<endl;
    } while (s != "end");
}

It is merely a matter of how you type the input.

It works, but I don't know why it is working....by simply doing cin >> s;

Why is the cin working but not the getline?

Could you explain in a simple way?

Why are the two reacting so differently.

Originally Posted by immy

It works, but I don't know why it is working....by simply doing cin >> s;

Why is the cin working but not the getline?

Could you explain in a simple way?

Why are the two reacting so differently.

The idea of getline is to read line by line (or token by token, by changing the delimiter) into strings. Hence, your "multiple values in on a single line" is read as a single value.

The idea behind cin >> s is formatted input, i.e., based on the type of the right hand side argument of operator>> and on other formatting instructions, input is read. By default, using cin >> s skips leading whitespace, reads the input into the string, stopping when whitespace is encountered. Hence, repeated use of operator>> for std::string reads each of your "multiple values in on a single line".