spiral_print.cpp File Reference

Print the elements of a matrix traversing it spirally. More...

#include <iostream>

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Functions
void	genArray (int **a, int r, int c)
void	spiralPrint (int **a, int r, int c)
int	main ()

Detailed Description

Print the elements of a matrix traversing it spirally.

Function Documentation

genArray()

void genArray	(	int **	a,
		int	r,
		int	c
	)

Arrange sequence of numbers from '1' in a matrix form

Parameters

[out]	a	matrix to fill
[in]	r	number of rows
[in]	c	number of columns

                                     {
    int value = 1;
    for (int i = 0; i < r; i++) {
        for (int j = 0; j < c; j++) {
            a[i][j] = value;
            std::cout << a[i][j] << " ";
            value++;
        }
        std::cout << std::endl;
    }
}

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main()

int main

(

void

)

main function

           {
    int r, c;
    std::cin >> r >> c;
    int **a = new int *[r];
    for (int i = 0; i < r; i++) a[i] = new int[c];
 
    genArray(a, r, c);
    spiralPrint(a, r, c);
 
    for (int i = 0; i < r; i++) delete[] a[i];
    delete[] a;
    return 0;
}

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spiralPrint()

void spiralPrint	(	int **	a,
		int	r,
		int	c
	)

Traverse the matrix spirally and print the sequence of elements

Parameters

[in]	a	matrix to read from
[in]	r	number of rows
[in]	c	number of columns

Print start row

Print the end col

Print the end row

Print the start Col

                                        {
    int startRow = 0, endRow = r - 1;
    int startCol = 0, endCol = c - 1;
    int cnt = 0;
 
    while (startRow <= endRow && startCol <= endCol) {
        /// Print start row
        for (int i = startCol; i <= endCol; i++, cnt++) {
            std::cout << a[startRow][i] << " ";
        }
        startRow++;
 
        /// Print the end col
        for (int i = startRow; i <= endRow; i++, cnt++) {
            std::cout << a[i][endCol] << " ";
        }
        endCol--;
 
        /// Print the end row
        if (cnt == r * c) {
            break;
        }
 
        for (int i = endCol; i >= startCol; i--, cnt++) {
            std::cout << a[endRow][i] << " ";
        }
        endRow--;
 
        /// Print the start Col
        if (cnt == r * c) {
            break;
        }
        for (int i = endRow; i >= startRow; i--, cnt++) {
            std::cout << a[i][startCol] << " ";
        }
        startCol++;
    }
}