Question

Given a matrix, clockwise-rotate elements in it. Please add code to problem3.cpp and the makefile. I have also given the main_problem3.cpp and problem3.h to test.

problem3.cpp:::

#include "problem3.h"

// A function to rotate a matrix mat[][MAX]
void rotatematrix(int m, int n, int mat[][MAX])
{
// your code here   
}

Makefile:::

all : problem3.o
   g++ -o mainp3 # your code here

problem3.o : problem3.h problem3.cpp
   # your code here

clean:
   rm -f *.o mainp3

main_problem3.cpp:::

#include <iostream>
#include "problem3.h"
using namespace std;

int main(){
int m=4,n=8;
int a[][100] = { {1, 2, 3, 4, 5, 6,7,8},
{5, 6, 7, 8, 9, 10, 11,12},
{9, 10, 11, 12, 13, 14,15,16},
{13, 14, 15, 16, 17, 18, 19, 20} };
  
for (int i=0; i<m; i++){
for (int j=0; j<n; j++)
cout << a[i][j] << " ";
cout << endl;
}
cout<<endl;
  
rotatematrix(m,n,a);
  
for (int i=0; i<m; i++){
for (int j=0; j<n; j++)
cout << a[i][j] << " ";
cout << endl;
}
}

problem3.h:::

#ifndef LAB4_PROBLEM3
#define LAB4_PROBLEM3
#define MAX 100
void rotatematrix(int m, int n, int mat[][MAX]);
#endif

Answer 1

Hello Learner,

Thanks for the question.

As per the question I need to write the code for rotatematrix that will rotate a given matrix in clockwise direction. As you haven’t specified the angle to which it needs to be rotated I have assumed it to the shift one element in clockwise direction.

Code:

void rotatematrix(int m,int n,int mat[][100]){

{

int row = 0, col = 0;

int prev, cur;

while (row < m && col < n)

{

if (row + 1 == m || col + 1 == n)

break;

prev = mat[row + 1][col];

for (int i = col; i < n; i++)

{

cur = mat[row][i];

mat[row][i] = prev;

prev = cur;

}

row++;

for (int i = row; i < m; i++)

{

cur = mat[i][n-1];

mat[i][n-1] = prev;

prev = cur;

}

n--;

if (row < m){

for (int i = n-1; i >= col; i--)

{

cur = mat[m-1][i];

mat[m-1][i] = prev;

prev = cur;

}

}

m--;

if (col < n)

{

for (int i = m-1; i >= row; i--)

{

cur = mat[i][col];

mat[i][col] = prev;

prev = cur;

}

}

col++;

}

}

}

Please let me know if you have any further questions.

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