примеры для решения задач stepik

stepik_samples.cpp

void strcat(char *to, const char *from)
{
    while (*to){
        to++;
    }

    while (*from){
        *to = *from;
        from++;
        to++;
    }
    *to='\0';
}
propo
propropofffa
пропо
пропропоавыфав


#include <iostream>

// int * m;

// m = new int[1000];
// delete [] m;

// m = new int(50);
// delete m;

char *resize(const char *str, unsigned size, unsigned new_size)
{
    char * m = new char[new_size];
    for (auto i=0; i<new_size; i++){
        m[i] = str[i];
    }
    delete [] str;
    return m;
}

char *getline()
{
    char ch;
    unsigned size = 10;
    char * str = new char[size];
    unsigned cnt = 0;
    while (std::cin.get(ch) && ch != '\n') {
        str[cnt] = ch;
        if (cnt == size) {
            str = resize(str, size, size+10);
            size+=10;
        }
        cnt++;
    }
    return str;
}

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=====================================================================

#include <iostream>

// int * m;

// m = new int[1000];
// delete [] m;

// m = new int(50);
// delete m;

char *resize(const char *str, unsigned size, unsigned new_size) {
    char * m = new char[new_size];
    for (auto i=0; i<size; i++){
        m[i] = str[i];
    }
    delete [] str;
    str = 0;
    return m;
}

char *getline() {
    char ch;
    unsigned size = 1024*1024;
    char * str = new char[size];
    unsigned cnt = 0;
    while (std::cin.get(ch) && ch != '\n') {
        str[cnt] = ch;
        if (cnt == size) {
            str = resize(str, size, size*2);
            size*=2;
        }
        cnt++;
    }
    str[cnt] = '\0';
    return str;
}

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=====================================================================

int ** m = new int * [5];
for (size_t i=0; i!=5; i++)
    m[i] = new int[4];

int ** create_array2d(size_t a, size_t b){
    int ** m = new int * [a];
    for (size_t i=0; i!=a; i++)
        m[i] = new int[b];
}

void free_array2d(int ** m, size_t a, size_t b){
    for (size_t i=0; i!=a; i++)
        delete [] m[i];
    delete [] m;
}


int ** m = new int * [5];
m[0] = new int [5 * 4];
for (size_t i=1; i!=5; i++)
    m[i] = m[i-1] + 4;

int ** create_array2d(size_t a, size_t b){
    int ** m = new int *[a];
    m[0] = new int[a * b];
    for (size_t i=1; i!=a; i++)
        m[i] = m[i-1] + b;
    return m;
}

void free_array2d(int ** m, size_t a, size_t b){
    delete [] m[0];
    delete [] m;
}


int *temp = m[0];
m[0] = m[minRow];
m[minRow] = temp;


int ** create_array2d(auto a, auto b){
    int ** m = new int * [a];
    m[0] = new int[a * b];
    for (auto i=1; i!=a; i++)
        m[i] = m[i-1] + b;
    return m;
}

int ** transpose(const int * const * m, unsigned rows, unsigned cols)
{
    int ** nm = create_array2d(cols, rows);
    for (auto i=0; i!=rows; i++){
        for (auto j=0; j!=cols; j++){
            nm[j][i] = m[i][j];
        }
    }
    return nm;
}


=====================================================================
=====================================================================

#include <cmath>

doublel length(Segment s){
    double dx = s.p1.x - s.p2.x;
    double dy = s.p1.y - s.p2.y;
    return sqrt(dx*dx + dy*dy);
}


=====================================================================
=====================================================================


struct Point {
    Point() {
        x = y =0;
    }
    Point(double x, double y) {
        this->x = x;
        this->y = y;
    }
    double x;
    double y;
}

Point P1;
Point p2(3,7);
-------------------------------
struct Point {
    Point() : x(0), y(0)
    {}
    Point(double x, double y) x(x), y(y)
    {}
    double x;
    double y;
}
-------------------------------
struct Point {
    Point(double x=0, double y=0)
        : x(x), y(y)
    {}
    double x;
    double y;
}
Point p1;
Point p2(2);
Point p3(3,4);
-------------------------------
struct Segment {
    Segment() {}
    Segment(double length)
        : p2(length, 0)
    {}
    Point p1;
    Point p2;
}

Segment s1;
Segment s2(10);
Segment s3 = 20;

struct Point {
    explicit Point (double x=0, double y=0)
        : x(x), y(y)
    {}
    double x;
    double y;
}

Point p1;
Point p2(2);
Point p3(3,4);
Point p4 = 5; //error
-------------------------------

struct Segment {
    Segment(Point p1, Point p2)
        : p1(p1), p2(p2)
    {}
    Point p1;
    Point p2;
}

Segment s1; // error
Segment s2(Point(), Point(2,1));
-------------------------------

struct Point {
    explicit Point (double x=0, double y=0)
    : x(x), y(y) {}
    double x;
    double y;
}

Point p1;   // определение переменной
Point p2();    // бьявление функции

double k=5.1;
Point p3(int(k));   // обьявление функции
Point p4((int)k);   // определение переменной
-------------------------------

struct IntArray {
    explicit IntArray(size_t size)
        : size(size)
        , data(new int[size])
        {}

    ~IntArray() {
        delete [] data;
    }

    size_t size;
    int * data;
}
-------------------------------