While i use two cin input to enter a data into the array the first input is working fine but the second array input are getting arbitrary values

Question

I am trying to take two input and save it to two different arrays but the first array is input is getting stored perfectly but the second input value is arbitrary I don't get why is it happing

#include<iostream>
using namespace std;
int main()
{
    int n;
    int points = 20, fouls = 10;
    cin>>n;
    int arr[n], fls[n], pt[n], fl[n];
    for(int i = 0; i < n; i++){
        cin >> arr[i] >>fls[i];
    }
 
    for(int i = 0; i< n;i++){
        pt[i]= arr[i] * points;
        fl[i] = fls[i] * fouls;

        // arr[i] = arr[i] - fls[i];
        // cout<<pt[i]<<" ";
        cout<<fl[i]<<" ";

    }

    // int max = arr[0];
    // for(int i =1; i <n;i++){
    //     if(arr[i]>max){
    //         max = arr[i];
    //     }
    // }
    // cout<<max;
    return 0;
}

Output

Do you realize your input makes `arr[] = { 40, 50, 4 }` and `fls[] = { 30, 2, 20 }`? Is that what you intend? — acraig5075, May 04 '21 at 08:41

score 0 · Answer 1 · answered May 04 '21 at 08:43

What you write is what you get.

In this for loop

for(int i = 0; i < n; i++){
    cin >> arr[i] >>fls[i];
}

you are entering sequentially the following values

40 30 50 2 4 20

So

arr[0] = 40 fls[0] = 30  // first iteration of the loop
arr[1] = 50 fls[1] = 2   // second iteration of the loop
arr[2] = 4  fls[2] = 20  // third iteration of the loop

Then in this for loop

for(int i = 0; i< n;i++){
    pt[i]= arr[i] * points;
    fl[i] = fls[i] * fouls;

    // arr[i] = arr[i] - fls[i];
    // cout<<pt[i]<<" ";
    cout<<fl[i]<<" ";

}

you will get

fl[0] = 300, fl[1] = 20 fl[2] = 200

This output is shown on the screenshot.

Pay attention to that variable length arrays is not a standard C++ feature. You should use std::vector<int>.

While i use two cin input to enter a data into the array the first input is working fine but the second array input are getting arbitrary values

1 Answers1