не моё

#include <iostream>
#include <cstdio>
#include <cstring>
#include <conio.h>
#include <stdlib.h>
#include <stdarg.h>
#define clr system("cls")
#define pause system("pause")

using namespace std;

int strlen1(char s[]) {
    int numb = 0;
    while (s[numb] != 0)
        numb++;
    return numb;
}

int strlen2(char s[]) {
    int numb = 0;
    for (int i = 0; i < 256; i++) {
        if (s[i] != 0)
            numb++;
        else break;
    }
    return numb;
}

int strlen3(char s[]) {
    int numb = 0, i = 0;
begin:if (s[i] != 0) {
    numb++;
    i++;
    goto begin;
}
      return numb;
}

int strlen4(char s[]) {
    int numb = 0, i = 0;
    char *s1 = s;
begin:if (*s1 != 0) {
    numb++;
    *s1++;
    goto begin;
}
      return numb;
}


char* strcopy1(char *dest, char *s, int p, int k) {
    int lens = strlen1(s);
    if (p < 1 || k < 1)
        return dest;
    if (p + k > lens)
        k = lens - p;
    for (int i = 0; i < k; i++, p++) {
        dest[i] = s[p];
    }
    return dest;
}

char* strcopy2(char *dest, char *s, int p, int k) {
    int lens = strlen1(s);
    if (p < 1 || k < 1 || p > strlen1(s))
        return dest;
    if (p + k > lens)
        k = lens - p;
    int i = 0;
    p++;
    while (k != 0 && dest != '\0') {
        *(dest + i) = *(s + p - 1);
        i++;
        p++;
        k--;
    }
    return dest;
}

char* strcopy3(char *dest, char *s, int p, int k) {
    int lens = strlen1(s);
    if (p < 1 || k < 1 || p > strlen1(s))
        return dest;
    if (p + k > lens)
        k = lens - p;
    for (int i = 0; s[i]; p++, i++) {
        if (s[p] == 0 || i == k)
            break;
        dest[i] = s[p];
    }
    return dest;
}

char* strcopy4(char *dest, char *s, int p, int k) {
    int lens = 0;
    lens = strlen1(s);
    if (p < 1 || k < 1 || p > lens) {
        return dest;
    }
    if (p + k > lens)
        k = lens - p;
    int i = 0;
begin:if (k > 0) {
    dest[i] = s[p];
    p++;
    i++;
    k--;
    goto begin;
}
      return dest;
}

void strins1(char *sub, char *s, int p) {
    int lens = strlen1(s);
    if (p > lens)
        p = lens;
    if (p < 1)
        p = 0;
    char tmp[256]{ 0 };
    for (int i = 0, k = p; k < strlen1(s); i++, k++)
        tmp[i] = s[k];
    for (int i = 0, k = p; k < strlen1(sub) + p; i++, k++)
        s[k] = sub[i];
    for (int i = 0, k = (strlen1(sub) + p); k < (strlen1(s) + strlen1(sub)); i++, k++)
        s[k] = tmp[i];
}

void strins2(char *sub, char *s, int p) {
    int lens = strlen1(s);
    if (p > lens)
        p = lens;
    if (p < 1)
        p = 0;
    for (int i = p, k = 0; i < strlen1(sub) + p; i++, k++) {
        for (int m = lens; m >= i; m--) {
            *(s + m + 1) = *(s + m);
            printf("s = '%s'\n", s);
        }
        *(s + i) = *(sub + k);
    }
}

void strins3(char *sub, char *s, int p) {
    int lensub = strlen1(sub);
    int lens = strlen1(s), N = lens;
    if (p > lens)
        p = lens;
    if (p < 1)
        p = 0;
    for (int i = p; i < lensub + p; i++) {
        while (N + 1 != i) {
            s[N + 1] = s[N];
            N--;
        }
        N = lens;
        s[i] = sub[i - p];
    }
}

void strins4(char *sub, char *s, int p) {
    int lens = strlen1(s);
    int lensub = strlen1(sub);
    if (p > lens)
        p = lens;
    if (p < 1)
        p = 0;
    int i = p, k = 0;
begin1:int m = lens;
begin2:s[m + 1] = s[m];
    m--;
    if (m >= i)
        goto begin2;
    s[i] = sub[k];
    i++, k++;
    if (i < lensub + p)
        goto begin1;
}

int strcmp1(char *s1, char *s2) {
    int lens1 = strlen1(s1), lens2 = strlen1(s2), i = 0, s = 0;
    if (lens1 == 0 || lens2 == 0)
        return s;
    while (s1[i] != 0 && s2[i] != 0) {
        if (s1[i] > s2[i]) {
            s = 1;
            break;
        }
        else {
            if (s1[i] < s2[i]) {
                s = -1;
                break;
            }
        }
        i++;
    }
    return s;
}

int strcmp2(char *s1, char *s2) {
    while (*s1 && (*s1 == *s2))
    {
        s1++; s2++;
    }
    return *s1 == *s2 ? 0 : *s1 > *s2 ? 1 : -1;
}

int strcmp3(char *s1, char *s2) {
    return *s1 > *s2 ? 1 : *s1 < *s2 ? -1 : *s1 ? strcmp3(s1 + 1, s2 + 1) : 0;
}

int strcmp4(char *s1, char *s2) {
    int i, lens1(strlen(s1));
    for (i = 0; i < lens1; i++)
    {
        if (s1[i] < s2[i])
            return -1;
        if (s1[i] > s2[i])
            return 1;
    }
    return s2[i] ? -1 : 0;
}

void strdel1(char *s, int p, int k) {
    p--;
    int lens = strlen1(s);
    if (p + k > lens)
        k = lens - p;
    int k1 = k;
    for (int j = 0; j < k; j++) {
        for (int i = p + k1; i < strlen1(s); i++) {
            printf("s = '%s'\n", s);
            s[i] = s[i + 1];
        }
        k1--;
    }
}

void strdel2(char *s, int p, int k) {
    int lens = strlen1(s);
    if (p + k > lens)
        k = lens - p;
    p--;
    if (p <= lens) {
        while (strlen1(s) != lens - k) {
            for (int i = p + 1; i < lens; i++)
                *(s + i) = *(s + i + 1);
        }
    }
}

void strdel3(char *s, int p, int k) {
    int lens = strlen1(s);
    if (p + k > lens)
        k = lens - p;
    int i = p + k - 1;
begin:if (k > 0) {
    for (int j = i; j < strlen1(s); j++)
        s[j] = s[j + 1];
    printf("s = '%s'\n", s);
    k--;
    i--;
    goto begin;
}
}

void strdel4(char *s, int p, int k) {
    int lens = strlen1(s);
    if (p + k > lens)
        k = lens - p;
    if (k > 0) {
        int N = lens - k;
        char *st = new char[N];
        int pt = p;
        for (int i = 0, j = 0; i < lens; i++) {
            if (i != pt) {
                st[j] = s[i];
                j++;
            }
            else if ((pt - p) < k - 1)
                pt++;
        }
        for (int i = lens - 1; i >= 0; i--)
            s[i] = 0;
        for (int i = 0; i < N; i++) {
            s[i] = st[i];
        }
    }
}

int strpos1(char *sub, char *s) {
    int pos = -1, lensub = strlen1(sub), lens = strlen1(s), j = 0;
    if (lensub > lens)
        return -1;
    for (int i = 0; *(s + i) != 0; i++) {
        j = 0;
        if (*(sub + j) == *(s + i)) {
            pos = i + 1;
            for (j = 0; j < lensub; j++, i++) {
                if (*(sub + j) != *(s + i)) {
                    pos = -1;
                    break;
                }
                if (j == lensub - 1)
                    return pos;
            }
            i--;
        }
    }
    return pos;
}

int strpos2(char *sub, char *s) {
    int pos = -1, i = 0, j = 0, lens = strlen1(s), lensub = strlen1(sub);
    if (lensub > lens)
        return -1;
    while (s[i] != 0) {
        j = 0;
        if (s[i] == sub[j]) {
            pos = i + 1;
            while (j != lensub) {
                if (s[i] != sub[j]) {
                    pos = -1;
                    break;
                }
                if (j == lensub - 1)
                    return pos;
                j++;
                i++;
            }
        }
        else
            i++;
    }
    return pos;
}

int strpos3(char *sub, char *s) {
    int pos = -1;
    int i = 0, j = 0, lensub = strlen1(sub), lens = strlen1(s);
    if (lensub > lens)
        return -1;
    i--;
begin:
    if (i == lens - 1)
        return -1;
    i++;
body:if (s[i] == sub[j]) {
    if (pos == -1)
        pos = i + 1;
    if (j == lensub - 1)
        return pos;
    if (s[i + 1] != sub[j + 1]) {
        pos = -1;
        j = 0;
        goto begin;
    }
    j++; i++;
    goto body;
}
     else
    goto begin;
}

int strpos4(char *sub, char *s) {
    int pos = -1, lens = strlen1(s) - 1, len = strlen1(s) - 1, lensub = strlen1(sub);
    int i = 0, j = 0, b = lensub;
    while (len > 0) {
    startiter:if (b == 0)
        return pos;
              if (s[0] == sub[j]) {
                  if (pos == -1)
                      pos = lens - len + 1;
                  j++;
                  b--;
              }
              else {
                  pos = -1;
                  j = 0;
                  if (b != lensub) {
                      b = lensub;
                      goto startiter;
                  }
              }
              for (int i = 0; i < len; i++)
                  s[i] = s[i + 1];
              len--;
    }
    return pos;
}

void testlen(char *s1) {
    cout << "strlen1(\"" << s1 << "\")=: " << strlen1(s1) << endl;
    cout << "strlen2(\"" << s1 << "\")=: " << strlen2(s1) << endl;
    cout << "strlen3(\"" << s1 << "\")=: " << strlen3(s1) << endl;
    cout << "strlen4(\"" << s1 << "\")=: " << strlen4(s1) << endl;
    cout << endl;
}

void testcpy(char *dest, char *s, int p, int k) {
    char dest1[256]{ 0 }; int i = 0;
    while (dest[i] != 0) {
        dest1[i] = dest[i];
        i++;
    }
    cout << "strcopy1(\"" << dest1 << "\",\"" << s << "\"," << p << "," << k << ")=: ";
    cout << "\"" << strcopy1(dest1, s, p, k) << "\"" << endl;
    for (int i = strlen1(dest1) - 1; i >= 0; i--)
        dest1[i] = 0;
    i = 0;
    while (dest[i] != 0) {
        dest1[i] = dest[i];
        i++;
    }
    cout << "strcopy2(\"" << dest1 << "\",\"" << s << "\"," << p << "," << k << ")=: ";
    cout << "\"" << strcopy2(dest1, s, p, k) << "\"" << endl;
    for (int i = strlen1(dest1) - 1; i >= 0; i--)
        dest1[i] = 0;
    i = 0;
    while (dest[i] != 0) {
        dest1[i] = dest[i];
        i++;
    }
    cout << "strcopy3(\"" << dest1 << "\",\"" << s << "\"," << p << "," << k << ")=: ";
    cout << "\"" << strcopy3(dest1, s, p, k) << "\"" << endl;
    for (int i = strlen1(dest1) - 1; i >= 0; i--)
        dest1[i] = 0;
    i = 0;
    while (dest[i] != 0) {
        dest1[i] = dest[i];
        i++;
    }
    cout << "strcopy4(\"" << dest1 << "\",\"" << s << "\"," << p << "," << k << ")=: ";
    cout << "\"" << strcopy4(dest1, s, p, k) << "\"" << endl;
    cout << endl;
}

void testins(char *sub, char *s, int p) {
    char s1[256]{ 0 }; int i = 0;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    printf("s1 = '%s'\n", s1);
    i = 0;
    cout << "strins1(\"" << sub << "\",\"" << s1 << "," << p << ")=: ";
    strins1(sub, s1, p);
    cout << "\"" << s1 << "\"" << endl;
    for (int i = strlen1(s1) - 1; i >= 0; i--)
        s1[i] = 0;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strins2(\"" << sub << "\",\"" << s1 << "," << p << ")=: ";
    strins2(sub, s1, p);
    cout << "\"" << s1 << "\"" << endl;
    for (int i = strlen1(s1) - 1; i >= 0; i--)
        s1[i] = 0;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strins3(\"" << sub << "\",\"" << s1 << "," << p << ")=: ";
    strins3(sub, s1, p);
    cout << "\"" << s1 << "\"" << endl;
    for (int i = strlen1(s1) - 1; i >= 0; i--)
        s1[i] = 0;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strins4(\"" << sub << "\",\"" << s1 << "," << p << ")=: ";
    strins4(sub, s1, p);
    cout << "\"" << s1 << "\"" << endl;
    cout << endl;
}

void testcmp(char *s1, char *s2) {
    cout << "strcmp1(\"" << s1 << "\",\"" << s2 << "\")=: ";
    cout << strcmp1(s1, s2) << endl;

    cout << "strcmp2(\"" << s1 << "\",\"" << s2 << "\")=: ";
    cout << strcmp2(s1, s2) << endl;

    cout << "strcmp3(\"" << s1 << "\",\"" << s2 << "\")=: ";
    cout << strcmp3(s1, s2) << endl;

    cout << "strcmp4(\"" << s1 << "\",\"" << s2 << "\")=: ";
    cout << strcmp4(s1, s2) << endl;
    cout << endl;
}

void testdel(char *s, int p, int k) {
    char s1[256]{ 0 }; int i = 0;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strdel1(\"" << s1 << "\"," << p << "," << k << ")=: ";
    strdel1(s1, p, k);
    cout << "\"" << s1 << "\"" << endl;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strdel2(\"" << s1 << "\"," << p << "," << k << ")=: ";
    strdel2(s1, p, k);
    cout << "\"" << s1 << "\"" << endl;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strdel3(\"" << s1 << "\"," << p << "," << k << ")=: ";
    strdel3(s1, p, k);
    cout << "\"" << s1 << "\"" << endl;
    while (s[i] != 0) {
        s1[i] = s[i];
        i++;
    }
    i = 0;
    cout << "strdel4(\"" << s1 << "\"," << p << "," << k << ")=: ";
    strdel4(s1, p, k);
    cout << "\"" << s1 << "\"" << endl;
    cout << endl;
}

void teststrpos(char *sub, char *s) {
    cout << "strpos1(\"" << sub << "\",\"" << s << "\")=: ";
    cout << strpos1(sub, s) << endl;
    cout << "strpos2(\"" << sub << "\",\"" << s << "\")=: ";
    cout << strpos2(sub, s) << endl;
    cout << "strpos3(\"" << sub << "\",\"" << s << "\")=: ";
    cout << strpos3(sub, s) << endl;
    cout << "strpos4(\"" << sub << "\",\"" << s << "\")=: ";
    cout << strpos4(sub, s) << endl;
    cout << endl;
}

int main()
{
    setlocale(LC_ALL, "rus");
menu:while (true) {
    clr;
    cin.clear();
    cout << "1.strlen\n2.strcopy\n3.strins\n4.strcmp\n5.strdel\n6.strpos\n\n\n0.Выход";
    switch (_getch()) {
    case '1': {
        clr;
        char s1[] = "hello";
        testlen(s1);
        char s2[] = "";
        testlen(s2);
        char s3[] = "012";
        testlen(s3);
        char s4[] = "-12345";
        testlen(s4);
        pause;
        goto menu;
    }
    case '2': {
        clr;
        int p, k;
        char dest1[25] = "rty";
        char s1[] = "012345";
        p = 0;
        k = 3;
        testcpy(dest1, s1, p, k);
        char s2[] = "012345";
        p = 20;
        k = 1;
        char dest2[] = "";
        testcpy(dest2, s2, p, k);
        char s3[] = "012345";
        p = 4;
        k = 10;
        char dest3[] = "";
        testcpy(dest3, s3, p, k);
        char s4[] = "0helloboom343";
        p = 2;
        k = 8;
        char dest4[] = "";
        testcpy(dest4, s4, p, k);
        pause;
        goto menu;
    }
    case '3': {
        clr;
        int p;
        char sub1[] = "ab", s1[] = "012345678";
        p = 0;
        testins(sub1, s1, p);
        char sub2[] = "ab", s2[] = "012345678";
        p = 3;
        testins(sub2, s2, p);
        char sub3[] = "ab", s3[] = "012345678";
        p = 10;
        testins(sub3, s3, p);
        char sub4[] = "ab", s4[] = "012345678";
        p = 0;
        testins(sub4, s4, p);
        pause;
        goto menu;
    }
    case '4': {
        clr;
        char s11[] = "hello", s12[] = "hellor";
        testcmp(s11, s12);
        char s21[] = "hello", s22[] = "boomboom";
        testcmp(s21, s22);
        char s31[] = "bello", s32[] = "booms";
        testcmp(s31, s32);
        char s41[] = "", s42[] = "";
        testcmp(s41, s42);
        pause;
        goto menu;
    }
    case '5': {
        clr;
        int p, k;
        char s1[] = "012345";
        p = 2; k = 30;
        testdel(s1, p, k);
        char s2[] = "012345";
        p = 20; k = 3;
        testdel(s2, p, k);
        char s3[] = "012345abcde";
        p = 0; k = 6;
        testdel(s3, p, k);
        char s4[] = "012345";
        p = 1; k = 3;
        testdel(s4, p, k);
        pause;
        goto menu;
    }
    case '6': {
        clr;
        char sub1[] = "345", s1[] = "0123456";
        teststrpos(sub1, s1);
        char sub2[] = "123", s2[] = "012123";
        teststrpos(sub2, s2);
        char sub3[] = "55", s3[] = "444545544";
        teststrpos(sub3, s3);
        char sub4[] = "ab", s4[] = "acdeabcde";
        teststrpos(sub4, s4);
        pause;
        goto menu;
    }
    case '0': exit(0);
    }
}
}