What is the role of "x" in the array's brackets and the loop?
(The code below is an example that was used to demonstrate some logic in C#)
#include <iostream>
#include <string>
using namespace std;
int main() {
int myArr[5];
//Why is 'x' present in "myArr[x] and what is the use of for loop
for(int x=0; x<5; x++) {
myArr[x] = 42;
cout << x << ": " << myArr[x] << endl;
}
}
Your code is (almost) equivalent to:
#include <iostream>
int main() {
for(int x=0; x<5; x++) {
std::cout << x << ": " << 42 << std::endl;
}
}
The output is
0: 42
1: 42
2: 42
3: 42
4: 42
And your code produces same output.
Why the author of the code uses an array, only the author of the code can know.
why is 'x' present in myArr[x]
Because x is used as index into the array myArr.
what is the role of for loop in this code
The role of the for loop is to execute the body of the loop 5 times. x has the value n in the n-th iteration.
Up Edit: I strictly recomend you to get C++ book, and read it. Or watch tutorials of C++ coding. Here is not to good way of learning new language
the build of for loop like this: for ( init; condition; increment )
At first part, you need to initialize variable, name doesen't important. In your case, you named 'x' you can name whatever you want. And you define starting point of x.
In your case, Your x is integer, and x starts from 0
In condition part, you declare the condition, in your case, when x<5, loop is continuing (in true values)
And the last part of for loop, you declare the incriment to end loop somewhere. x++ means x = x+1
So in for loop argument is like this "Start from 0, count one by one untill x reachs 5" and untill reachs 5, do something (do what is in brackets {} )
Array is array of datas, and myArr[x] means, "myArr's x. Data"
And because of for loop, it'll go from zero to fourth data. In array
And all of data will be equal 42.
Like, first data of myArr[x] (don't forget x is an integer) (myArr[0]) will equal 42.
The second will equal 42 and so on. For loop decides how long x variable will go. But, Array must be declared that size due to prevent out of range errors.
(Scroll down for a summary of everything I just said)
The array ‘myArr’ has 5 integer elements, each of which can be accessed through their index.
For example, to access the first element in myArr, we can use: myArr[0]
(Note that indices start from 0, so the first element in any array is at index 0)
Keeping this “index-property” of arrays in mind, we can implement “for” loops with arrays. For loops work well with arrays because they sequentially go through a certain data set, and arrays are essentially a row-wise collection of elements of the same data type. So using a for loop, we can go through each element one by one (and perform whatever processes we need to).
In the for-loop, the variable “x” is used to go through the array. The initial value of 0 for x will make myArr[x] equal to myArr[0], which is the first element of myArr. In the second iteration of the for-loop the same code is run, however, this time the value of x is 1, and thus instead of myArr[0], myArr[1] is used; i.e: the second element is referenced.
In summary, the for loop just iterates over all the elements in the array and the local variable x is just used as a reference to the index of the element currently being used in the loop.
I hope this answers your question :)
