Home Online Manual
Top
Back: int declarations
Forward: int operations
FastBack: ideal
FastForward: intmat
Up: int
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

4.6.2 int expressions

An int expression is:

  1. a sequence of digits (if the number represented by this sequence is too large to fit into the range of integers it is automatically converted to the type number, if a basering is defined)
  2. an identifier of type int
  3. a function returning int
  4. an expression involving ints and the arithmetic operations +, -, *, div (/), % (mod), or ^
  5. a boolean expression
  6. a type cast to int

Note: Variables of type int represent the compiler integers and are, therefore, limited in their range (see Limitations). If this range is too small the expression must be converted to the type number over a ring with characteristic 0.


Example:

 
12345678901; // too large
==> 12345678901
typeof(_);
==> bigint
ring r=0,x,dp;
12345678901;
==> 12345678901
typeof(_);
==> bigint
// Note: 11*13*17*100*200*2000*503*1111*222222
// returns a machine integer:
11*13*17*100*200*2000*503*1111*222222;
==> // ** int overflow(*), result may be wrong
==> // ** int overflow(*), result may be wrong
==> // ** int overflow(*), result may be wrong
==> // ** int overflow(*), result may be wrong
==> -1875651584
// using the type cast number for a greater allowed range
number(11)*13*17*100*200*2000*503*1111*222222;
==> 12075748128684240000000
ring rp=32003,x,dp;
12345678901;
==> 12345678901
typeof(_);
==> bigint
intmat m[2][2] = 1,2,3,4;
m;
==> 1,2,
==> 3,4 
m[2,2];
==> 4
typeof(_);
==> int
det(m);
==> -2
m[1,1] + m[2,1] == trace(m);
==> 0
! 0;
==> 1
1 and 2;
==> 1
intvec v = 1,2,3;
def d =transpose(v)*v;    // scalarproduct gives an 1x1 intvec
typeof(d);
==> intvec
int i = d[1];             // access the first (the only) entry in the intvec
ring rr=31,(x,y,z),dp;
poly f = 1;
i = int(f);               // cast to int
// Integers may be converted to constant  polynomials by an assignment,
poly g=37;
// define the constant polynomial g equal to the image of
// the integer 37 in the actual coefficient field, here it equals 6
g;
==> 6

See Type conversion and casting; number.