Thread: Confusion

Help please.

Code:

#include <iostream>

using namespace std;

int mult(int x,int y);

int main()
{
    int x;
    int y;
    
    cout<<"Please input two numbers to be multiplied:";
    cin>>x>>y;
    cin.ignore();
    cout<<"The product of these two numbers is:" <<mult (x,y)<<"\n";
    cin.get();
}
int mult(int x, int y)
{
    return x*y;
    
}

E:\Programs\Programing\Programs\Function.cpp: In function `int main()':
E:\Programs\Programing\Programs\Function.cpp:12: error: `cout' undeclared (first use this function)
E:\Programs\Programing\Programs\Function.cpp:12: error: (Each undeclared identifier is reported only once for each function it appears in.)
E:\Programs\Programing\Programs\Function.cpp:13: error: `cin' undeclared (first use this function)

Execution terminated


is it right?

The error will be obvious when it is pointed out... so, do you understand the error messages? They are basically telling you that cout and cin were not declared, but since you included <iostream>, they should be declared, right?

what is ionstream, cstdlib and the difference between them.

Recall the standard headers are <iostream> and <cstdlib>, not ionstream

<iostream> gives you access to std::cin and std::cout (and std::cerr and std::clog, and their wide character equivalents). <cstdlib> is the C++ version of <stdlib.h> from C, which gives you access to miscellaneous standard library utilities, including a pseudorandom number generator and C-style memory management functions.

the int<-- in the begining is what tells the whole program that those intergers will be used?

No. You may need to read a book, or go through the tutorials slowly. The int that you refer to (if I guessed correctly) declares that the function returns an int.

Is programing all numbers, and input should only be numbers?

At some fundamental level, programming is all numbers, but we tend to think at higher levels unless the subject matter specifically concerns numbers.

Originally Posted by Nestor

Yes its all good, but now i have question that are not specified in the tutorial,
what is ionstream, cstdlib and the difference between them.

Different headers contain different functions and objects, put simply.
And it's iostream, not ionstream.

the int<-- in the begining is what tells the whole program that those intergers will be used?

I don't know which int you're referring to, but the answer is still false.
Int is a type that tells the compiler what kind of type a variable is or what a function returns. It's applied to each function and variable, separately.

Is programing all numbers, and input should only be numbers?

No. You can input strings, too.
Although, in the basic computer architecture, strings are treated as numbers, but in a high level environment, they're strings, not numbers.