Thread: advice for newbies

Have you checked out this site's tutorials ?

This program when run will open a console. cout directs output to the std output stream which is in this case the monitor. Thus it will cause the message:

HEY, you, I'm alive! Oh, and Hello World!

To be displayed.

The cin.get() is a way to keep the console window open long enough for you to see the result of the program by waiting for the user to press any key.

well, you've stumbled into the right room...

here's some starters:

a varable declaration looks like this:

Code:

type name;
//for example:
int myvariable;

basically, the types you'll most likely be using are char, int, and float. a character is a single character, like 'A','a','B', or 'b'. as you may be able to tell, an 'A' is a different character from an 'a'. an integer is a whole number without a fraction. for example, 1,2,3 are all integers, 1.2 is not. floats are used to hold fractions/decimals, but they can also be used for integers. for example, 1,2.3,4.67 are all valid floating-point numbers.

first, we'll add. generally, what's on the left of the equal sign (the lvalue) must be the variable the sum will be saved to. this variable can also be a part of the addition. here are some examples:

Code:

int a,b,c,d,e;
a=b+c;  //add b and c and save it to a
a=a+d; //add a and d and save it to a
a+=e;   //add a and e and save it to a
a++;     //add one to a and save it to a
++a;     //add one to a and save it to a

now, to count something, you will most likely use an integer and start by setting it to zero, then adding 1 to it every time something happens. a variable used like this is called an accumulator. for example:

Code:

int counter=0;  //create an int called counter and set it to 0

for(int i=0;i<10;i++)  //a loop structure - will go around 10 times
{
    ++counter;  //increase counter by 1.  it's the same as counter=counter+1;
}

with averages, you want to add all the values and divide by the amount there is. one simple way to do this is like this:

Code:

#include<iostream>

int main()
{
    int score=0;    //this will be the accumulator - start at zero
    int temp;       //this is to hold each individual score
    int counter=0;  //this is to count the nubmer of scores
    
    for(int i=0;i<5;i++)  //a loop structure - will loop 5 times
    {
        std::cout<<"> ";        //output a prompt
        std::cin>>temp;         //take in an integer
        std::cin.ignore(1);
        
        score+=temp;    //add the value taken in to the rest of them
        counter++;      //increase the number of scores taken in
    }
    
    score/=counter; //divide the total scores by the amount taken in
    std::cout<<"Average: "<<score<<std::endl;   //output the average
    std::cin.get(); //wait for the user to press enter
    return 0;       //exit with a success value
}

Our text is "Programming in C++" by Dale and Weems, 3rd edition. It doesn't impress me with depth of explanation.

I think when you are learning any language, you need two books: a main book that you study exclusively, and another one to look up confusing stuff. I can recommend "Ivor Horton's Beginning C++". You can get it used in good condition for only $16 here(which is a great deal for a 900 page book):

http://dogbert.abebooks.com/servlet/...imagefield.y=0

Check the shipping charges--all the sellers charge different shipping, so the cheapest price may not be the cheapest book.

It also sounds like you have two issues: the math and the language. You have to have the math clear in your head before you start trying to write a program.

Declaring variables and simple arithmetic:

Code:

#include<iostream>
using namespace std;

int main()
{
    
    int num1;  //declare integer variable num1
    num1 = 10;  //assign a value to the variable num1
    cout<<num1<<endl;

    int num2 = 20;  //declare the variable and assign it a value
    cout<<num2<<endl;

    num1 = 100;
    cout<<num1<<endl;

    int sum = num1 + num2;  //sum equals 120
    cout<<sum<<endl;


    char ch = 'a'; //single quotes are a must
    cout<<ch<<endl;


    double d = 10.4;
    cout<<d<<endl;


    //Integer arithmetic chops off the decimal part
    int a = 5, b = 2;
    int sum2 = a/b;  //sum2 equals 2
    cout<<sum2<<endl;

    //decimal arithmetic
    double x = 5.0, y = 2.0;
    double sum3 = x/y; //sum3 equals 2.5
    cout<<sum3<<endl;

    return 0;

}

Simple function:

Code:

#include<iostream>
using namespace std;

void func1()
{
    cout<<"hello"<<endl;
}

int main()
{
    func1();
    
    return 0;

}

Functions must have a return type listed before the function name. In this case, the function doesn't return anything, so it's return type is 'void'--meaning 'nothing'. The function is executed in main with the statement: func1();

Simple function, 1 'parameter'

Code:

#include<iostream>
using namespace std;

void func1(int a)
{
    cout<<a<<endl;
}

int main()
{
    func1(3);
    
    return 0;
}

This time the function has a 'parameter'. That means the function expects a number will be sent to it. The 'parameter' is a variable that stores the number sent to the function. Then, inside the function the number will be used in some way. In main, the function is called with this statement:

func1(3);

and the number that the function is expecting is put between the parenthesis--you can think of it as emailing the number to the function. The number you put between the parentheses must match the type of the parameter listed for the function--in this case the parameter is int a. The integer number 3 is sent to the function, and it is stored in the variable a. When the function receives the value, it displays 'a' using cout.

Simple function, 1 parameter, returns a value

Code:

#include<iostream>
using namespace std;

int func1(int a)
{
    int sum = 2 * a;
    return sum;
}

int main()
{
    int result = func1(3);
    cout<<result<<endl;
    
    return 0;
}

This time the function returns a value. It is not returning 'void' anymore, so in front of the function name, you have to indicate the return type. Inside the function, the return statement returns sum, which is of type int, so the return type of the function must be int. Since the function is returning a value, you want to capture that value when you call the function in main(). I declared the variable 'result' to capture and store the return value of func1(). 'result' must have the same type as the function's return type.

Wow we are sure getting a lot of members?!