C Program to implement Radix Sort


Levels of difficulty: / perform operation:

Radix sort is an algorithm. Radix Sort sorts the elements by processing its individual digits. Radix sort processing the digits either by Least Significant Digit(LSD) method or by Most Significant Digit(MSD) method.

C Program

#include <stdio.h>
#define MAX 100
#define SHOWPASS
void print(int *a, int n) {
	int i;
	for (i = 0; i < n; i++)
	  printf("%d\t", a[i]);
}
void radix_sort(int *a, int n) {
	int i, b[MAX], m = 0, exp = 1;
	for (i = 0; i < n; i++) {
		if (a[i] > m)
		   m = a[i];
	}
	while (m / exp > 0) {
		int box[10] = {
			0
		}
		;
		for (i = 0; i < n; i++)
		   box[a[i] / exp % 10]++;
		for (i = 1; i < 10; i++)
		   box[i] += box[i - 1];
		for (i = n - 1; i >= 0; i--)
		   b[--box[a[i] / exp % 10]] = a[i];
		for (i = 0; i < n; i++)
		   a[i] = b[i];
		exp *= 10;
		#ifdef SHOWPASS
		  printf("\n\nPASS   : ");
		print(a, n);
		#endif
	}
}
int main() {
	int arr[MAX];
	int i, num;
	printf("\nEnter total elements (num < %d) : ", MAX);
	scanf("%d", &num);
	printf("\nEnter %d Elements : ", num);
	for (i = 0; i < num; i++)
	  scanf("%d", &arr[i]);
	printf("\nARRAY  : ");
	print(&arr[0], num);
	radix_sort(&arr[0], num);
	printf("\n\nSORTED  : ");
	print(&arr[0], num);
	return 0;
}





Quantitative Aptitude
Reasoning
Programming
Interview