Task: Euler's sum of powers conjecture



C#: using System;

namespace EulerSumOfPowers {
    class Program {
        const int MAX_NUMBER = 250;

        static void Main(string[] args) {
            bool found = false;
            long[] fifth = new long[MAX_NUMBER];

            for (int i = 1; i <= MAX_NUMBER; i++) {
                long i2 = i * i;
                fifth[i - 1] = i2 * i2 * i;
            }

            for (int a = 0; a < MAX_NUMBER && !found; a++) {
                for (int b = a; b < MAX_NUMBER && !found; b++) {
                    for (int c = b; c < MAX_NUMBER && !found; c++) {
                        for (int d = c; d < MAX_NUMBER && !found; d++) {
                            long sum = fifth[a] + fifth[b] + fifth[c] + fifth[d];
                            int e = Array.BinarySearch(fifth, sum);
                            found = e >= 0;
                            if (found) {
                                Console.WriteLine("{0}^5 + {1}^5 + {2}^5 + {3}^5 = {4}^5", a + 1, b + 1, c + 1, d + 1, e + 1);
                            }
                        }
                    }
                }
            }
        }
    }
}







COBOL:        IDENTIFICATION DIVISION.
       PROGRAM-ID. EULER.
       DATA DIVISION.
       FILE SECTION.
       WORKING-STORAGE SECTION.
       1   TABLE-LENGTH CONSTANT 250.
       1   SEARCHING-FLAG     PIC 9.
        88  FINISHED-SEARCHING VALUE IS 1
                               WHEN SET TO FALSE IS 0.
       1  CALC.
        3  A               PIC 999 USAGE COMPUTATIONAL-5.
        3  B               PIC 999 USAGE COMPUTATIONAL-5.
        3  C               PIC 999 USAGE COMPUTATIONAL-5.
        3  D               PIC 999 USAGE COMPUTATIONAL-5.
        3  ABCD            PIC 9(18) USAGE COMPUTATIONAL-5.
        3  FIFTH-ROOT-OFFS PIC 999 USAGE COMPUTATIONAL-5.
        3  POWER-COUNTER   PIC 999 USAGE COMPUTATIONAL-5.
        88 POWER-MAX       VALUE TABLE-LENGTH.
       
       1   PRETTY.
        3  A               PIC ZZ9.
        3  FILLER          VALUE "^5 + ".
        3  B               PIC ZZ9.
        3  FILLER          VALUE "^5 + ".
        3  C               PIC ZZ9.
        3  FILLER          VALUE "^5 + ".
        3  D               PIC ZZ9.
        3  FILLER          VALUE "^5 = ".
        3  FIFTH-ROOT-OFFS PIC ZZ9.
        3  FILLER          VALUE "^5.".

       1   FIFTH-POWER-TABLE   OCCURS TABLE-LENGTH TIMES
                               ASCENDING KEY IS FIFTH-POWER
                               INDEXED BY POWER-INDEX.
        3  FIFTH-POWER PIC 9(18) USAGE COMPUTATIONAL-5.


       PROCEDURE DIVISION.
       MAIN-PARAGRAPH.
           SET FINISHED-SEARCHING TO FALSE.
           PERFORM POWERS-OF-FIVE-TABLE-INIT.
           PERFORM VARYING
               A IN CALC
               FROM 1 BY 1 UNTIL A IN CALC = TABLE-LENGTH

               AFTER B IN CALC
               FROM 1 BY 1 UNTIL B IN CALC = A IN CALC

               AFTER C IN CALC
               FROM 1 BY 1 UNTIL C IN CALC = B IN CALC

               AFTER D IN CALC
               FROM 1 BY 1 UNTIL D IN CALC = C IN CALC

               IF FINISHED-SEARCHING
                   STOP RUN
               END-IF

               PERFORM POWER-COMPUTATIONS

           END-PERFORM.

       POWER-COMPUTATIONS.

           MOVE ZERO TO ABCD IN CALC.

           ADD FIFTH-POWER(A IN CALC)
               FIFTH-POWER(B IN CALC)
               FIFTH-POWER(C IN CALC)
               FIFTH-POWER(D IN CALC)
                   TO ABCD IN CALC.

           SET POWER-INDEX TO 1.

           SEARCH ALL FIFTH-POWER-TABLE
               WHEN FIFTH-POWER(POWER-INDEX) = ABCD IN CALC
                      MOVE POWER-INDEX TO FIFTH-ROOT-OFFS IN CALC
                      MOVE CORRESPONDING CALC TO PRETTY
                      DISPLAY PRETTY END-DISPLAY
                      SET FINISHED-SEARCHING TO TRUE
           END-SEARCH

           EXIT PARAGRAPH.

       POWERS-OF-FIVE-TABLE-INIT.
           PERFORM VARYING POWER-COUNTER FROM 1 BY 1 UNTIL POWER-MAX
               COMPUTE FIFTH-POWER(POWER-COUNTER) = 
                   POWER-COUNTER *
                   POWER-COUNTER *
                   POWER-COUNTER *
                   POWER-COUNTER *
                   POWER-COUNTER 
               END-COMPUTE
           END-PERFORM.
           EXIT PARAGRAPH.

       END PROGRAM EULER.