unexpexted output in c++ 2D array

Question

problem

i/o formats

sample test case

For a given two-dimensional integer array/list of size (N x M), print the array/list in a sine wave order, i.e, print the first column top to bottom, next column bottom to top and so on.

I am unable to get the expected output for this problem. Please find my code below:

#include <bits/stdc++.h>
using namespace std;

void wavePrint(int input[][2], int nRows, int mCols)
{
    //Write your code here
    for(int i=0;i<mCols;i++){
        int j=0;
        for(;j<nRows;j++){
            cout<<input[j][i]<<" ";
        }
        i++;
        for(;j>=0;j--){
            cout<<input[j][i]<<" ";
        }
    }
}




int main()
{
    
        int input[][2]={{5,6},{2,4}};
        wavePrint(input, 2, 2);
        cout << endl;
    
}

Answer 1

Since I do not have enough reputation to comment, the only thing I can do is answer.

Your primary issue is that you are incrementing the i loop index inside the loop. You don't need to/want to do this.

Walk through your code and track the variable values on each line (or use a debugger to do this) and you will see what the output looks like and where you've gone wrong.