Computational Physics - Department of Physics

2.5 Additional Features of C++ and Fortran 33

Table 2.5 lists several relational and arithmetic operators. Logical operators in C++ and

arithmetic operators relation operators
operator effect operator effect
− Subtraction > Greater than

• Addition >= Greater or equal
  ∗ Multiplication < Less than
  / Division <= Less or equal
  %or MOD Modulus division == Equal
  −− Decrement != Not equal
  ++ Increment
  Table 2.5Relational and arithmetic operators. The relation operators act between two operands. Note that
  the increment and decrement operators++and−−are not available in Fortran.

Fortran are listed in 2.6. while Table 2.7 shows bitwise operations.

Logical operators
C++ Effect Fortran
0 False value .FALSE.
1 True value .TRUE.
!x Logical negation .NOT.x
x&& y Logical AND x.AND.y
x||y Logical inclusive OR x.OR.y
Table 2.6List of logical operators in C++ and Fortran.

Bitwise operations
C++ Effect Fortran
~i Bitwise complement NOT(j)
i&jBitwise and IAND(i,j)
i^jBitwise exclusive or IEOR(i,j)
i|jBitwise inclusive or IOR(i,j)
i<<jBitwise shift left ISHFT(i,j)
i>>nBitwise shift right ISHFT(i,-j)
Table 2.7List of bitwise operations.

C++ offers also interesting possibilities for combined operators. These are collected in
Table 2.8.

Expression meaning expression meaning

a += b; a = a + b; a -= b; a = a - b;

a*= b; a = a*b; a /= b; a = a / b;

a %= b; a = a % b; a «= b; a = a « b;

a »= b; a = a » b; a &= b; a = a & b;

a |= b; a = a | b; a∧= b; a = a∧b;

Table 2.8C++ specific expressions.

Finally, we show some special operators pertinent to C++ only. The first one is the?oper-
ator. Its action can be described through the following example