The Program in C++ Program to Find Deficient numbers between given two numbers is given below:

#include <iostream>
using namespace std;

int main() {
  int num1, num2, sum;
  cout<<"Hello Codeauri Family,enter the two numbers here to find the deficient numbers between them;\n";
  cout << "Enter the first number: ";
  cin >> num1;
  cout << "Enter the second number: ";
  cin >> num2;

  cout << "The deficient numbers between " << num1 << " and " << num2 << " are: " << endl;
  for (int i = num1; i <= num2; i++) {
    sum = 0;
    for (int j = 1; j <= i/2; j++) {
      if (i % j == 0) {
        sum += j;
      }
    }
    if (sum < i) {
      cout << i << " ";
    }
  }

  return 0;
}

Output:

Hello Codeauri Family,enter the two numbers here to find the deficient numbers between them;
Enter the first number: 1
Enter the second number: 1000
The deficient numbers between 1 and 1000 are:
1 2 3 4 5 7 8 9 10 11 13 14 15 16 17 19 21 22 23 25 26 27 29 31 32 33 34 35 37 38 39 41 43 44 45 46 47 49 50 51 52 53 55 57 58 59 61 62 63 64 65 67 68 69 71 73 74 75 76 77 79 81 82 83 85 86 87 89 91 92 93 94 95 97 98 99 101 103 105 106 107 109 110 111 113 115 116 117 118 119 121 122 123 124 125 127 128 129 130 131 133 134 135 136 137 139 141 142 143 145 146 147 148 149 151 152 153 154 155 157 158 159 161 163 164 165 166 167 169 170 171 172 173 175 177 178 179 181 182 183 184 185 187 188 189 190 191 193 194 195 197 199 201 202 203 205 206 207 209 211 212 213 214 215 217 218 219 221 223 225 226 227 229 230 231 232 233 235 236 237 238 239 241 242 243 244 245 247 248 249 250 251 253 254 255 256 257 259 261 262 263 265 266 267 268 269 271 273 274 275 277 278 279 281 283 284 285 286 287 289 290 291 292 293 295 296 297 298 299 301 302 303 305 307 309 310 311 313 314 315 316 317 319 321 322 323 325 326 327 328 329 331 332 333 334 335 337 338 339 341 343 344 345 346 347 349 351 353 355 356 357 358 359 361 362 363 365 367 369 370 371 373 374 375 376 377 379 381 382 383 385 386 387 388 389 391 393 394 395 397 398 399 401 403 404 405 406 407 409 410 411 412 413 415 417 418 419 421 422 423 424 425 427 428 429 430 431 433 434 435 436 437 439 441 442 443 445 446 447 449 451 452 453 454 455 457 458 459 461 463 465 466 467 469 470 471 472 473 475 477 478 479 481 482 483 484 485 487 488 489 491 493 494 495 497 499 501 502 503 505 506 507 508 509 511 512 513 514 515 517 518 519 521 523 524 525 526 527 529 530 531 533 535 536 537 538 539 541 542 543 545 547 548 549 551 553 554 555 556 557 559 561 562 563 565 566 567 568 569 571 573 574 575 577 578 579 581 583 584 585 586 587 589 590 591 592 593 595 596 597 598 599 601 602 603 604 605 607 609 610 611 613 614 615 617 619 621 622 623 625 626 627 628 629 631 632 633 634 635 637 638 639 641 643 645 646 647 649 651 652 653 655 656 657 658 659 661 662 663 664 665 667 668 669 670 671 673 674 675 676 677 679 681 682 683 685 686 687 688 689 691 692 693 694 695 697 698 699 701 703 705 706 707 709 710 711 712 713 715 716 717 718 719 721 722 723 724 725 727 729 730 731 733 734 735 737 739 741 742 743 745 746 747 749 751 752 753 754 755 757 758 759 761 763 764 765 766 767 769 771 772 773 775 776 777 778 779 781 782 783 785 787 788 789 790 791 793 794 795 796 797 799 801 802 803 805 806 807 808 809 811 813 814 815 817 818 819 821 823 824 825 826 827 829 830 831 833 835 837 838 839 841 842 843 844 845 847 848 849 850 851 853 854 855 856 857 859 861 862 863 865 866 867 869 871 872 873 874 875 877 878 879 881 883 884 885 886 887 889 890 891 892 893 895 897 898 899 901 902 903 904 905 907 908 909 911 913 914 915 916 917 919 921 922 923 925 926 927 929 931 932 933 934 935 937 938 939 941 943 944 946 947 949 950 951 953 955 956 957 958 959 961 962 963 964 965 967 969 970 971 973 974 975 976 977 979 981 982 983 985 986 987 988 989 991 993 994 995 997 998 999

Pro-Tips💡

This program takes two integer inputs from the user and then finds all the deficient numbers between them.

The outer loop iterates i from num1 to num2.

The inner loop calculates the sum of proper divisors of i, and the if statement checks if the sum is less than i.

If it is, i is a deficient number, and the program outputs it.