YAPC::EU 2018 Glasgow Update!

Task/Permutations/C/permutations-1.c

@@ -0,0 +1,54 @@
+#include <stdio.h>
+int main (int argc, char *argv[]) {
+//here we check arguments
+	if (argc < 2) {
+        printf("Enter an argument. Example 1234 or dcba:\n");
+        return 0;
+	}
+//it calculates an array's length
+        int x;
+        for (x = 0; argv[1][x] != '\0'; x++);
+//buble sort the array
+	int f, v, m;
+	 for(f=0; f < x; f++) {
+    	 for(v = x-1; v > f; v-- ) {
+     	 if (argv[1][v-1] > argv[1][v]) {
+	m=argv[1][v-1];
+	argv[1][v-1]=argv[1][v];
+	argv[1][v]=m;
+    }
+  }
+}
+
+//it calculates a factorial to stop the algorithm
+    char a[x];
+	int k=0;
+	int fact=k+1;
+             while (k!=x) {
+                   a[k]=argv[1][k];
+               	   k++;
+		  fact = k*fact;
+                   }
+                   a[k]='\0';
+//Main part: here we permutate
+           int i, j;
+           int y=0;
+           char c;
+          while (y != fact) {
+          printf("%s\n", a);
+          i=x-2;
+          while(a[i] > a[i+1] ) i--;
+          j=x-1;
+          while(a[j] < a[i] ) j--;
+      c=a[j];
+      a[j]=a[i];
+      a[i]=c;
+i++;
+for (j = x-1; j > i; i++, j--) {
+  c = a[i];
+  a[i] = a[j];
+  a[j] = c;
+      }
+y++;
+   }
+}