SUBROUTINE EASTER (YEAR,ESTDAY,ESTMON) C C IN MEMORIAM KARL FRIEDRICH GAUSS C C INPUT PARAMETER C YEAR TO COMPUTE THE EASTER DAY 1700 TO 2099 INTEGER YEAR C OUTPUT PARAMETER C MONTH OF EASTERN 3 OR 4 (MARCH OR APRIL) INTEGER ESTMON, C DAY OF EASTERN RANGES FROM 1 TO 31 * ESTDAY C C CONSTANTS FOR 17TH, 18TH, 19TH, 20TH CENTURY INTEGER Y(4),Z(4), * R1,R2,R3,R4,R5,TEMP,CNTURY INTEGER NCOND EXTERNAL NCOND DATA Y,Z /22,23,24,24,3,4,5,5/ C C C THE CENTURY WANTED --> CNTURY CNTURY=YEAR/100-16 C R1=MOD(YEAR,19) R2=MOD(YEAR,4) R3=MOD(YEAR,7) R4=(R1*19+Y(CNTURY))/30 R5=(2*R2+4*R3+6*R4+Z(CNTURY))/7 TEMP=R4+R5+22 C TEMP HOLDS EASTER DAY PAST THE FIRST OF MARCH TEMP=NCOND(TEMP.EQ.56 .AND. R1.GT.10 .AND. R4.EQ.18,TEMP-7, * TEMP.GT.56,TEMP-7,TEMP) ESTMON=NCOND(TEMP.GT.31,4,3) ESTDAY=NCOND(TEMP.GT.31,TEMP-31,TEMP) RETURN END