Standard Template Library Programmer's Guide

The function object overview, Adaptable Binary Predicate, equal_to , greater , less , greater_equal , less_equal

Category: functors

Component type: type

Less is a function object. Specifically, it is an Adaptable Binary Predicate, which means it is a function object that tests the truth or falsehood of some condition. If f is an object of class less and x and y are objects of class T , then f(x,y) returns true if x < y and false otherwise.

Finds the first negative element in a list.

list L;

…

list::iterator first_negative = find_if(L.begin(), L.end(), bind2nd(less(), 0));

assert(first_negative == L.end() || *first_negative < 0);

Defined in the standard header functional, and in the nonstandard backward-compatibility header function.h.

Adaptable Binary Predicate, DefaultConstructible

T is LessThan Comparable.

binary_function.

All of less 's members are defined in the Adaptable Binary Predicate and DefaultConstructible requirements. less does not introduce any new members.

The function object overview, Strict Weak Ordering, Adaptable Binary Predicate, LessThan Comparable, equal_to , not_equal_to , greater , greater_equal , less_equal

Category: functors

Component type: type

Greater is a function object. Specifically, it is an Adaptable Binary Predicate, which means it is a function object that tests the truth or falsehood of some condition. If f is an object of class greater and x and y are objects of class T , then f(x,y) returns true if x > y and false otherwise.

Sort a vector in descending order, rather than the default ascending order.

vector V;

…

sort(V.begin(), V.end(), greater());

Defined in the standard header functional, and in the nonstandard backward-compatibility header function.h.

Adaptable Binary Predicate, DefaultConstructible

T is LessThan Comparable.

binary_function .

All of greater 's members are defined in the Adaptable Binary Predicate and DefaultConstructible requirements. Greater does not introduce any new members.

The function object overview, Adaptable Binary Predicate, LessThan Comparable, equal_to , not_equal_to , less , greater_equal , less_equal

Category: functors

Component type: type

Less_equal is a function object. Specifically, it is an Adaptable Binary Predicate, which means it is a function object that tests the truth or falsehood of some condition. If f is an object of class less_equal and x and y are objects of class T , then f(x,y) returns true if x <= y and false otherwise.

Finds the first non-positive element in a list.

list L;

…

list::iterator first_nonpositive = find_if(L.begin(), L.end(), bind2nd(less_equal(), 0));

assert(first_nonpositive == L.end() || *first_nonpositive <= 0);

Defined in the standard header functional, and in the nonstandard backward-compatibility header function.h.

Adaptable Binary Predicate, DefaultConstructible

T is LessThan Comparable.

binary_function.

All of less_equal 's members are defined in the Adaptable Binary Predicate and DefaultConstructible requirements. Less_equal does not introduce any new members.