Create prims.c

prims.c

@@ -0,0 +1,100 @@
+#include<stdio.h>
+#include<conio.h>
+
+int n, cost[10][10];
+
+void prim() {
+   int i, j, startVertex, endVertex;
+   int k, nr[10], temp, minimumCost = 0, tree[10][3];
+
+   /* For first smallest edge */
+   temp = cost[0][0];
+   for (i = 0; i < n; i++) {
+      for (j = 0; j < n; j++) {
+         if (temp > cost[i][j]) {
+            temp = cost[i][j];
+            startVertex = i;
+            endVertex = j;
+         }
+      }
+   }
+   /* Now we have fist smallest edge in graph */
+   tree[0][0] = startVertex;
+   tree[0][1] = endVertex;
+   tree[0][2] = temp;
+   minimumCost = temp;
+
+   /* Now we have to find min dis of each vertex from either
+    startVertex or endVertex by initialising nr[] array
+    */
+
+   for (i = 0; i < n; i++) {
+      if (cost[i][startVertex] < cost[i][endVertex])
+         nr[i] = startVertex;
+      else
+         nr[i] = endVertex;
+   }
+
+   /* To indicate visited vertex initialise nr[] for them to 100 */
+   nr[startVertex] = 100;
+   nr[endVertex] = 100;
+
+   /* Now find out remaining n-2 edges */
+   temp = 99;
+   for (i = 1; i < n - 1; i++) {
+      for (j = 0; j < n; j++) {
+         if (nr[j] != 100 && cost[j][nr[j]] < temp) {
+            temp = cost[j][nr[j]];
+            k = j;
+         }
+      }
+      /* Now i have got next vertex */
+      tree[i][0] = k;
+      tree[i][1] = nr[k];
+      tree[i][2] = cost[k][nr[k]];
+      minimumCost = minimumCost + cost[k][nr[k]];
+      nr[k] = 100;
+
+      /* Now find if k is nearest to any vertex
+       than its previous near value */
+
+      for (j = 0; j < n; j++) {
+         if (nr[j] != 100 && cost[j][nr[j]] > cost[j][k])
+            nr[j] = k;
+      }
+      temp = 99;
+   }
+   /* Now i have the answer, just going to print it */
+   printf("\nThe min spanning tree is:- ");
+   for (i = 0; i < n - 1; i++) {
+      for (j = 0; j < 3; j++)
+         printf("%d", tree[i][j]);
+      printf("\n");
+   }
+
+   printf("\nMin cost : %d", minimumCost);
+}
+
+void main() {
+   int i, j;
+   clrscr();
+
+   printf("\nEnter the no. of vertices :");
+   scanf("%d", &n);
+
+   printf("\nEnter the costs of edges in matrix form :");
+   for (i = 0; i < n; i++)
+      for (j = 0; j < n; j++) {
+         scanf("%d", &cost[i][j]);
+      }
+
+   printf("\nThe matrix is : ");
+   for (i = 0; i < n; i++) {
+      for (j = 0; j < n; j++) {
+         printf("%d\t", cost[i][j]);
+      }
+      printf("\n");
+   }
+   prim();
+   getch();
+}