Postman Sort Algorithm in C

This C Program implements Postman Sort Algorithm.

Here is source code of the C Program implements Postman Sort Algorithm. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/* 
```

 * C Program to Implement Postman Sort Algorithm

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void arrange(int,int);
```
```
int array[100], array1[100];
```

int i, j, temp, max, count, maxdigits = 0, c = 0;

```
 
```
```
void main()
```
```
{
```
```
    int t1, t2, k, t, n = 1;
```
```
 
```
```
    printf("Enter size of array :");
```
```
    scanf("%d", &count);
```

    printf("Enter elements into array :");

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    for (i = 0; i < count; i++)
```
```
    {
```
```
        scanf("%d", &array[i]);
```

        array1[i] = array[i];

```
    }
```
```
    for (i = 0; i < count; i++)
```
```
    {
```

        t = array[i];        /*first element in t */

```
        while(t > 0)
```
```
        {
```
```
            c++;
```

            t = t / 10;        /* Find MSB */

```
        }
```
```
        if (maxdigits < c) 
```

            maxdigits = c;   /* number of digits of a each number */

```
        c = 0;
```
```
    }
```
```
    while(--maxdigits) 
```
```
        n = n * 10;      
```
```
 
```
```
    for (i = 0; i < count; i++)
```
```
    {
```

        max = array[i] / n;        /* MSB - Dividnng by perticular base */

```
        t = i;
```

        for (j = i + 1; j < count;j++)

```
        {
```
```
            if (max > (array[j] / n))
```
```
            {
```

                max = array[j] / n;   /* greatest MSB */

```
                t = j;
```
```
            }
```
```
        }
```
```
        temp = array1[t];
```
```
        array1[t] = array1[i];
```
```
        array1[i] = temp;
```
```
        temp = array[t];
```
```
        array[t] = array[i];
```
```
        array[i] = temp;
```
```
    }
```
```
    while (n >= 1)
```
```
    {
```
```
        for (i = 0; i < count;)
```
```
        {
```
```
            t1 = array[i] / n;
```

            for (j = i + 1; t1 == (array[j] / n); j++);

```
                arrange(i, j);
```
```
            i = j;
```
```
        }
```
```
        n = n / 10;
```
```
    }
```

    printf("\nSorted Array (Postman sort) :");

```
    for (i = 0; i < count; i++)
```
```
        printf("%d ", array1[i]);
```
```
    printf("\n");
```
```
}
```
```
 
```

/* Function to arrange the of sequence having same base */

```
void arrange(int k,int n)
```
```
{
```
```
    for (i = k; i < n - 1; i++)
```
```
    {
```
```
        for (j = i + 1; j < n; j++)
```
```
        {
```
```
            if (array1[i] > array1[j])
```
```
            {
```
```
                temp = array1[i];
```
```
                array1[i] = array1[j];
```
```
                array1[j] = temp;
```
```
                temp = (array[i] % 10);
```

                array[i] = (array[j] % 10);

```
                array[j] = temp;
```
```
            }
```
```
        }
```
```
    }
```
```
}
```

$ cc postman.c
$ a.out
/* Average case */
 
Enter size of array :8
Enter elements into array :170
45
90
75
802
24
2
66
 
Sorted Array (Postman sort) :2 24 45 66 75 90 170 802 
 
$ a.out
/* Best case */
Enter size of array :7
Enter elements into array :25
64
185
136
36
3645
45
 
Sorted Array (Postman sort) :25 36 45 64 136 185 3645 
 
$ a.out
/* Worst case */
Enter size of array :8
Enter elements into array :15
214
166
0836
98
6254
73
642
 
Sorted Array (Postman sort) :15 73 98 166 214 642 836 6254

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