PC World Komputer 1997 May/Pcwk0597.iso/borland/cb/setup/cbuilder/data.z/ALG2.CPP

C/C++ Source or Header | 1997-02-28 | 5KB | 184 lines

/**************************************************************************
 *
 * alg2.cpp - test program for STL generic algorithm that search for
 *    elements that satisfy a condition.  Section 12.3
 *
 * $Id: alg2.cpp,v 1.2 1995/08/29 18:42:51 oberg Exp $
 *
 * $$RW_INSERT_HEADER "slyrs.cpp"
 *
 **************************************************************************/

# include <iostream.h>
# include <vector>
# include <list>
# include <algorithm>

# include <ctype.h>
# include <string>
# include <string.h>

using namespace std;

int randomInteger(int m)
{    return rand() % m; }

bool isLeapYear (unsigned int year)
{
    if (year % 1000 == 0)
        return true;
    if (year % 100 == 0)
        return false;
    if (year % 4 == 0)
        return true;
    return false;
}

bool operator < (const string & left, const string & right)
{    return left.compare(right) < 0; }

void split
    (const string & text, const string & separators, list<string> & words)
{
    int n = text.length();
    int start, stop;

    start = text.find_first_not_of(separators);
    while ((start >= 0) && (start < n)) {
        stop = text.find_first_of(separators, start);
        if ((stop < 0) || (stop > n)) stop = n;
        words.push_back (text.substr(start, stop-start));
        start = text.find_first_not_of(separators, stop+1);
        }

}


void find_test()
    // illustrate use of the find function
{
    cout << "Test of algorithm find" << endl;
    int vintageYears[] = {1967, 1972, 1974, 1980, 1995};

    vector<int>::iterator start = vintageYears;
    vector<int>::iterator stop = vintageYears + 5;

    vector<int>::iterator where = find_if(start, stop, isLeapYear);

    if (where != stop)
        cout << "first vintage leap year is " << *where << endl;
    else
        cout << "no vintage leap years" << endl;

    where = find(start, stop, 1995);

    if (where != stop)
        cout << "1995 is position " << where - start << " in sequence" << endl;
    else
        cout << "1995 does not occur in sequence" << endl;

}

void find_adjacent_test()
{
    cout << "Test of algorithm find adjacent" << endl;
    char * text = "The bookkeeper carefully opened the door";

    vector<char>::iterator start = text;
    vector<char>::iterator stop = text + strlen(text);

    vector<char>::iterator where = start;

    cout << "In the text " << text << endl;
    while ((where = adjacent_find(where, stop)) != stop) {
        cout << "double " << *where << " in position " << where - start << endl;
        ++where;
        }
}

void search_test()
    // illustrate the use of the search function
{
    cout << "Test of algorithm search" << endl;
    char * base = "aspirations";
    char * text = "ration";

    char * where = search(base, base + strlen(base), text, text + strlen(text));

    if (*where != '\0')
        cout << "substring begins in position " << where - base << endl;
    else
        cout << "substring does not occur in text" << endl;
}

void max_min_example ()
    // illustrate use of max_element and min_element algorithms
{
    cout << "Test of max and min algorithms " << endl;
    // make a vector of random numbers between 0 and 99
    vector<int> numbers(25);
    for (int i = 0; i < 25; i++)
        numbers[i] = randomInteger(100);

    // print the maximum
    vector<int>::iterator max =
        max_element(numbers.begin(), numbers.end());
    cout << "largest value was " << *max << endl;

        // example using strings
    string text =
        "it was the best of times, it was the worst of times.";
    list<string>words;
    split(text, " .,!:;", words);
    cout << "The smallest word is "
        << * min_element(words.begin(), words.end())
        << " and the largest word is "
        << * max_element(words.begin(), words.end())
        << endl;
}

void mismatch_test(char * a, char * b)
    // illustrate the use of the mismatch function
{
    pair<char *, char *> differPositions(0, 0);
    char * aDiffPos;
    char * bDiffPos;

    if (strlen(a) < strlen(b)) {
        differPositions = mismatch(a, a + strlen(a), b);
        aDiffPos = differPositions.first;
        bDiffPos = differPositions.second;
        }
    else {
        differPositions = mismatch(b, b + strlen(b), a);
        aDiffPos = differPositions.second;
        bDiffPos = differPositions.first;
        }

    cout << "string " << a;
    if (*aDiffPos == *bDiffPos)
        cout << " is equal to ";
    else if (*aDiffPos < *bDiffPos)
        cout << " is less than ";
    else
        cout << " is greater than ";
    cout << b << endl;
}

int main()
{
    cout << "STL generic algorithms -- Searching Algorithms" << endl;
    find_test();
    find_adjacent_test();
    search_test;
    max_min_example();
    mismatch_test("goody", "goody");
    mismatch_test("good", "goody");
    mismatch_test("goody", "good");
    mismatch_test("good", "fred");
    mismatch_test("fred", "good");

    cout << "End of search algorithms test program" << endl;
    return 0;
}