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Counter ( counter )

Definition

The class counter can be used during profiling to count how often certain code is executed. An example is given below.

#include < LEDA/system/counter.h >

Creation

counter c(const string& name, bool report_on_destruction = true)
    creates an instance c with the given name. If report_on_destruction is true, then the counter reports its value upon destruction. The initial value of the counter is zero.

counter c creates an unnamed instance c and sets the report_on_destruction flag to false. The initial value of the counter is zero.

Operations

void c.reset() sets the value of c to zero.

void c.set_value(const unsigned long val)
    sets the value of c to val.

const unsigned long c.get_value() returns the current value of c.

const unsigned long c.increment() increments c and returns its new value. (We also provide the operator ++.)

void c.set_name(const string& name)
    sets the name of c.

string c.get_name() returns the name of c.

void c.report_on_desctruction(bool do_report = true)
    sets the flag report_on_destruction to do_report.

bool c.will_report_on_desctruction()
    returns whether c will issue a report upon its destruction.

Example

In the example below we count how often the function fibonacci is executed.

#include <LEDA/system/counter.h>

unsigned fibonacci(unsigned n)
{
  static leda::counter cnt("fibonacci");
    // report upon destruction of cnt
  ++cnt;

  if (n < 1) return 0;
  else if (n == 1) return 1;
  else return fibonacci(n-1) + fibonacci(n-2);
}

int main()
{
  std::cout << fibonacci(40) << "\n";
  return 0; // reports "Counter(fibonacci) = 331160281" upon termination
}


next up previous contents index
Next: Two Tuples ( two_tuple Up: Simple Data Types and Previous: Timer ( timer )   Contents   Index
Christian Uhrig 2017-04-07