Parcurgerea in spirala a unei matrici

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//parcurgere matrice in spirala
#include <stdio.h>
#include <conio.h>
#include <math.h>


void citire(int m, int n, int a[20][20],char c)
{
for(int i=1;i<=m;i++)
  for(int j=1;j<=n;j++)
    {
      printf("%c[%i][%i]=",c,i,j);
      scanf("%d",&a[i][j]);
    }
}


void afisare(int m, int n, int a[20][20])
{
for(int i=1;i<=m;i++)
 {
  for(int j=1;j<=n;j++)
    printf(" %d ",a[i][j]);
    printf("n");
    }
}

void main()
{
int n;
int a[20][20],stsus,drsus,drjos,stjos,i,j;
printf("n=");
scanf("%d",&n);

 printf("nCitire matricen");
 citire(n,n,a,'A');
 printf("Afisare matrice n");
 afisare(n,n,a);
 printf("nParcurgere Spiralan");
 stsus=1;drsus=n;drjos=n;stjos=1;
 do
 {     // --->
 for(i=stsus;i<=drsus;i++)
     printf(" %d ",a[stsus][i]);
  stsus=stsus+1;
         //in jos
 for(i=stsus;i<=drjos;i++)
     printf(" %d ",a[i][drjos]);
 drjos=drjos-1;
                                                                   
          // <---
for(i=drjos;i>=stjos;i--)
     printf(" %d ",a[drjos+1][i]);

          // in sus
 for(i=drjos;i>=stsus;i--)
  printf(" %d ",a[i][stsus-1]);
  drsus=drsus-1;
  stjos=stjos+1;
  }
while(drjos>n/2);
getch();
}