C Collection of code snippets by Arne Vajhøj 
C (from articles on eksperten.dk / vajhoej.dk written sometime between 2004 and now) 
      PROGRAM OPS
      INTEGER*4 N,M
      REAL*8 X
      CHARACTER*16 S
      N=7
      M=5
      WRITE(*,*) N+M,N-M,N*M,N/M,MOD(N,M)
      WRITE(*,*) N.EQ.M,N.NE.M,N.LT.M,N.GT.M
      X=2.5
      WRITE(*,*) SQRT(X**2),LOG(EXP(X)),LOG10(10**X) 
      WRITE(*,*) ACOS(0.0),ASIN(1.0)
      WRITE(*,*) COSD(90.0),SIND(90.0)
      S='This is a test'
      WRITE(*,*) LEN(S),INDEX(S,'is'),S(6:7S)
      END