Today, we will explain a simple C program to construct a B tree. We have not used any number validation in this program as it is designed for beginners for learning purpose.
Copy below c program and execute it with c compiler to see the output of the program.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 | #include <stdio.h> #include <stdlib.h> #define MAX 4 #define MIN 2 struct btreeNode { int val[MAX + 1], count; struct btreeNode *link[MAX + 1]; }; struct btreeNode *root; /* creating new node */ struct btreeNode * createNode(int val, struct btreeNode *child) { struct btreeNode *newNode; newNode = (struct btreeNode *)malloc(sizeof(struct btreeNode)); newNode->val[1] = val; newNode->count = 1; newNode->link[0] = root; newNode->link[1] = child; return newNode; } /* Places the value in appropriate position */ void addValToNode(int val, int pos, struct btreeNode *node, struct btreeNode *child) { int j = node->count; while (j > pos) { node->val[j + 1] = node->val[j]; node->link[j + 1] = node->link[j]; j--; } node->val[j + 1] = val; node->link[j + 1] = child; node->count++; } /* split the node */ void splitNode (int val, int *pval, int pos, struct btreeNode *node, struct btreeNode *child, struct btreeNode **newNode) { int median, j; if (pos > MIN) median = MIN + 1; else median = MIN; *newNode = (struct btreeNode *)malloc(sizeof(struct btreeNode)); j = median + 1; while (j <= MAX) { (*newNode)->val[j - median] = node->val[j]; (*newNode)->link[j - median] = node->link[j]; j++; } node->count = median; (*newNode)->count = MAX - median; if (pos <= MIN) { addValToNode(val, pos, node, child); } else { addValToNode(val, pos - median, *newNode, child); } *pval = node->val[node->count]; (*newNode)->link[0] = node->link[node->count]; node->count--; } /* sets the value val in the node */ int setValueInNode(int val, int *pval, struct btreeNode *node, struct btreeNode **child) { int pos; if (!node) { *pval = val; *child = NULL; return 1; } if (val < node->val[1]) { pos = 0; } else { for (pos = node->count; (val < node->val[pos] && pos > 1); pos--); if (val == node->val[pos]) { printf("Duplicates not allowed\n"); return 0; } } if (setValueInNode(val, pval, node->link[pos], child)) { if (node->count < MAX) { addValToNode(*pval, pos, node, *child); } else { splitNode(*pval, pval, pos, node, *child, child); return 1; } } return 0; } /* insert val in B-Tree */ void insertion(int val) { int flag, i; struct btreeNode *child; flag = setValueInNode(val, &i, root, &child); if (flag) root = createNode(i, child); } /* copy successor for the value to be deleted */ void copySuccessor(struct btreeNode *myNode, int pos) { struct btreeNode *dummy; dummy = myNode->link[pos]; for (;dummy->link[0] != NULL;) dummy = dummy->link[0]; myNode->val[pos] = dummy->val[1]; } /* removes the value from the given node and rearrange values */ void removeVal(struct btreeNode *myNode, int pos) { int i = pos + 1; while (i <= myNode->count) { myNode->val[i - 1] = myNode->val[i]; myNode->link[i - 1] = myNode->link[i]; i++; } myNode->count--; } /* shifts value from parent to right child */ void doRightShift(struct btreeNode *myNode, int pos) { struct btreeNode *x = myNode->link[pos]; int j = x->count; while (j > 0) { x->val[j + 1] = x->val[j]; x->link[j + 1] = x->link[j]; } x->val[1] = myNode->val[pos]; x->link[1] = x->link[0]; x->count++; x = myNode->link[pos - 1]; myNode->val[pos] = x->val[x->count]; myNode->link[pos] = x->link[x->count]; x->count--; return; } /* shifts value from parent to left child */ void doLeftShift(struct btreeNode *myNode, int pos) { int j = 1; struct btreeNode *x = myNode->link[pos - 1]; x->count++; x->val[x->count] = myNode->val[pos]; x->link[x->count] = myNode->link[pos]->link[0]; x = myNode->link[pos]; myNode->val[pos] = x->val[1]; x->link[0] = x->link[1]; x->count--; while (j <= x->count) { x->val[j] = x->val[j + 1]; x->link[j] = x->link[j + 1]; j++; } return; } /* merge nodes */ void mergeNodes(struct btreeNode *myNode, int pos) { int j = 1; struct btreeNode *x1 = myNode->link[pos], *x2 = myNode->link[pos - 1]; x2->count++; x2->val[x2->count] = myNode->val[pos]; x2->link[x2->count] = myNode->link[0]; while (j <= x1->count) { x2->count++; x2->val[x2->count] = x1->val[j]; x2->link[x2->count] = x1->link[j]; j++; } j = pos; while (j < myNode->count) { myNode->val[j] = myNode->val[j + 1]; myNode->link[j] = myNode->link[j + 1]; j++; } myNode->count--; free(x1); } /* adjusts the given node */ void adjustNode(struct btreeNode *myNode, int pos) { if (!pos) { if (myNode->link[1]->count > MIN) { doLeftShift(myNode, 1); } else { mergeNodes(myNode, 1); } } else { if (myNode->count != pos) { if(myNode->link[pos - 1]->count > MIN) { doRightShift(myNode, pos); } else { if (myNode->link[pos + 1]->count > MIN) { doLeftShift(myNode, pos + 1); } else { mergeNodes(myNode, pos); } } } else { if (myNode->link[pos - 1]->count > MIN) doRightShift(myNode, pos); else mergeNodes(myNode, pos); } } } /* delete val from the node */ int delValFromNode(int val, struct btreeNode *myNode) { int pos, flag = 0; if (myNode) { if (val < myNode->val[1]) { pos = 0; flag = 0; } else { for (pos = myNode->count; (val < myNode->val[pos] && pos > 1); pos--); if (val == myNode->val[pos]) { flag = 1; } else { flag = 0; } } if (flag) { if (myNode->link[pos - 1]) { copySuccessor(myNode, pos); flag = delValFromNode(myNode->val[pos], myNode->link[pos]); if (flag == 0) { printf("Given data is not present in B-Tree\n"); } } else { removeVal(myNode, pos); } } else { flag = delValFromNode(val, myNode->link[pos]); } if (myNode->link[pos]) { if (myNode->link[pos]->count < MIN) adjustNode(myNode, pos); } } return flag; } /* delete val from B-tree */ void deletion(int val, struct btreeNode *myNode) { struct btreeNode *tmp; if (!delValFromNode(val, myNode)) { printf("Given value is not present in B-Tree\n"); return; } else { if (myNode->count == 0) { tmp = myNode; myNode = myNode->link[0]; free(tmp); } } root = myNode; return; } /* search val in B-Tree */ void searching(int val, int *pos, struct btreeNode *myNode) { if (!myNode) { return; } if (val < myNode->val[1]) { *pos = 0; } else { for (*pos = myNode->count; (val < myNode->val[*pos] && *pos > 1); (*pos)--); if (val == myNode->val[*pos]) { printf("Given data %d is present in B-Tree", val); return; } } searching(val, pos, myNode->link[*pos]); return; } /* B-Tree Traversal */ void traversal(struct btreeNode *myNode) { int i; if (myNode) { for (i = 0; i < myNode->count; i++) { traversal(myNode->link[i]); printf("%d ", myNode->val[i + 1]); } traversal(myNode->link[i]); } } int main() { int val, ch; while (1) { printf("1. Insertion\t2. Deletion\n"); printf("3. Searching\t4. Traversal\n"); printf("5. Exit\nEnter your choice:"); scanf("%d", &ch); switch (ch) { case 1: printf("Enter your input:"); scanf("%d", &val); insertion(val); break; case 2: printf("Enter the element to delete:"); scanf("%d", &val); deletion(val, root); break; case 3: printf("Enter the element to search:"); scanf("%d", &val); searching(val, &ch, root); break; case 4: traversal(root); break; case 5: exit(0); default: printf("U have entered wrong option!!\n"); break; } printf("\n"); } } |
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