kr(OAIP)3

#include <iostream>
#include <stdio.h>
#include <string>

using namespace std;

int str_len(char *s){
    int k = 0;
    while (s[k++]);
    return --k;
}


int atoi(char *s) { // задание 1
    int mn = 1;
    int ans = 0;
    for (int i = str_len(s) - 1; i >= 0; i--) {
        if (s[i] >= '0' && s[i] <= '9') {
            ans += (s[i] - '0') * mn;
            mn *= 10;
        }
        else return -1;
    }
    return ans;
}

void init(char *&s) { // воодит строку до нажатия Enter
    rewind(stdin);
    s = (char*)malloc(sizeof(char));
    s[0] = getchar();
    int i = 0;
    while (s[i] != '\n') {
        i++;
        s = (char*)realloc(s, (i + 1) * sizeof(char));
        s[i] = getchar();
    }
    s[i] = '\0';
}

void push_d(char *s, int l, int r) {
    for (int i = l; i < str_len(s) - (r - l) - 2; i++) {
        s[i] = s[i + (r - l) + 2];
    }
    s[str_len(s) - (r - l) - 2] = '\0';
}

void deleteword(char *s, int number) { // задание 2
    int n = 0;
    int i = 0;
    int l;
    int r;
    while (s[i]) {
        while (s[i] == ' ') i++;
        l = i;
        while (s[i] && s[i] != ' ')i++;
        r = i - 1;
        n++;
        if (n == number) {
            push_d(s, l, r);
            break;
        }

    }
}


void deletesymbol(char *s, char c) { // задание 3
    for (int i = 0; i < str_len(s); i++) {
        if (s[i] == c) {
            for (int j = i; j < str_len(s) - 1; j++) {
                s[j] = s[j + 1];
            }
            s[str_len(s) - 1] = '\0';
            i--;
        }
    }
}

void reverser(char *s, int l, int r) {
    int j = 0;
    for ( int i = l; i <= (l + r) / 2; i++) {
        swap(s[i], s[r - j]);
        j++;
    }
}

void swapper(char *s, int n1, int n2) { // задаиние 4
    if (n2 < n1) {
        swap(n1, n2);
    }
    int n = 0;
    int i = 0;
    int l,l1,l2;
    int r,r1,r2;
    while (s[i]) {
        while (s[i] == ' ') i++;
        l = i;
        while (s[i] && s[i] != ' ')i++;
        r = i - 1;
        n++;
        if (n == n1) {
            r1 = r;
            l1 = l;
        }
        if (n == n2) {
            r2 = r;
            l2 = l;
        }
    }
    reverser(s, l1, r2);
    r1 = l1;
    while (s[r1] && s[r1] != ' ') r1++;
    r1--;
    reverser(s, l1, r1);
    l2 = r2;
    while (s[l2] && s[l2] != ' ') l2--;
    l2++;
    reverser(s, l2, r2);
    reverser(s, r1 + 1, l2 - 1);
}

void inputer(char *s, char *inp, int number) { // задание 5
    int n = 0;
    int i = 0;
    int l;
    int r;
    while (s[i]) {
        while (s[i] == ' ') i++;
        l = i;
        while (s[i] && s[i] != ' ')i++;
        r = i - 1;
        n++;
        if (n == number) {
            s = (char *)realloc(s,(str_len(s) + str_len(inp) + 1) * sizeof(char));
            s[str_len(s) + str_len(inp) + 1] = '\0';
            s[str_len(s)] = '%';

            for (int i = str_len(s)-1; i > r; i--) {
                s[i] = s[i - str_len(inp) - 1];
            }
            s[r + 1] = ' ';
            for (int i = r + 2; i < r + 2 + str_len(inp); i++) {
                s[i] = inp[i - r - 2];
            }
        }

    }
}

int main()
{
    char *s = (char *)malloc(sizeof(char));
    char *inp = (char *)malloc(sizeof(char));
    free(s);
    free(inp);
    init(s);
    init(inp);
    //int a = atoi(s);
    //deleteword(s, 1);
    //deletesymbol(s, 'a');
    //swapper(s, 1, 2);
    //inputer(s, inp, 2);
}