5-dars: Sikllar — for

Dars haqida

Davomiyligi: 90 daqiqa Maqsad: Talaba for siklini tushunishi, har xil holatlarda ishlatishi va nested for'lar bilan ishlashi kerak.

1. Sikl nima?

Sikl (loop) — kodning takror-takror bajarilishi.

Scratch'da:

repeat 10
    move 10 steps

C'da:

for (int i = 0; i < 10; i++) {
    printf("Iteration %d\n", i);
}

Bir xil g'oya, boshqa sintaksis.

2. Nima uchun sikl?

Sikl'siz:

printf("1\n");
printf("2\n");
printf("3\n");
printf("4\n");
printf("5\n");
// ...100 marta...

Sikl bilan:

for (int i = 1; i <= 100; i++) {
    printf("%d\n", i);
}

Kod 5 qator, lekin 100 marta ishlaydi.

3. for sikli tuzilmasi

for (initialization; condition; update) {
    // body — har iteratsiyada ishlaydi
}

3 ta qism:

Misol — 0 dan 9 gacha:

for (int i = 0; i < 10; i++) {
    printf("%d ", i);
}

Natija: 0 1 2 3 4 5 6 7 8 9

Qadamma-qadam

1. i = 0
2. i < 10? → ROST
3. Body: printf("0 ")
4. i++  →  i = 1

1. i = 1
2. i < 10? → ROST
3. Body: printf("1 ")
4. i++  →  i = 2

... va h.k. ...

i = 9
2. i < 10? → ROST
3. Body: printf("9 ")
4. i++  →  i = 10

i = 10
2. i < 10? → YOLG'ON
3. Sikldan chiqadi

4. Asosiy for misollar

1 dan 10 gacha

for (int i = 1; i <= 10; i++) {
    printf("%d ", i);
}
// 1 2 3 4 5 6 7 8 9 10

Teskari: 10 dan 1 gacha

for (int i = 10; i >= 1; i--) {
    printf("%d ", i);
}
// 10 9 8 7 6 5 4 3 2 1

2 ga qadam

for (int i = 0; i <= 20; i += 2) {
    printf("%d ", i);
}
// 0 2 4 6 8 10 12 14 16 18 20

Toq raqamlar

for (int i = 1; i <= 20; i += 2) {
    printf("%d ", i);
}
// 1 3 5 7 9 11 13 15 17 19

5. Yig'indi hisoblash

int sum = 0;
for (int i = 1; i <= 100; i++) {
    sum += i;
}
printf("1+2+...+100 = %d\n", sum);
// 1+2+...+100 = 5050

6. O'rtacha hisoblash

int total = 0;
int count = 10;

for (int i = 1; i <= count; i++) {
    int ball = i * 10;  // misol — 10, 20, 30, ...
    total += ball;
}

double average = (double)total / count;
printf("O'rtacha: %.2f\n", average);

7. Faktorial

int n = 5;
int factorial = 1;

for (int i = 1; i <= n; i++) {
    factorial *= i;
}

printf("%d! = %d\n", n, factorial);
// 5! = 120

8. Continue va Break

break — sikldan chiqish

for (int i = 0; i < 100; i++) {
    if (i == 5) {
        break;  // sikl tugaydi
    }
    printf("%d ", i);
}
// 0 1 2 3 4

continue — keyingi iteratsiyaga

for (int i = 0; i < 10; i++) {
    if (i % 2 == 0) {
        continue;  // keyingi iteratsiyaga
    }
    printf("%d ", i);
}
// 1 3 5 7 9 (faqat toq)

9. Nested for — sikl ichida sikl

for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 3; j++) {
        printf("(%d, %d) ", i, j);
    }
    printf("\n");
}

Natija:

(1, 1) (1, 2) (1, 3) 
(2, 1) (2, 2) (2, 3) 
(3, 1) (3, 2) (3, 3)

Ko'paytirish jadvali

for (int i = 1; i <= 9; i++) {
    for (int j = 1; j <= 9; j++) {
        printf("%d * %d = %d\n", i, j, i * j);
    }
    printf("---\n");
}

10. Pattern (naqsh) chizish

Yulduzlar piramida

int n = 5;

for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= i; j++) {
        printf("*");
    }
    printf("\n");
}

Natija:

*
**
***
****
*****

Teskari piramida

for (int i = n; i >= 1; i--) {
    for (int j = 1; j <= i; j++) {
        printf("*");
    }
    printf("\n");
}

Natija:

*****
****
***
**
*

O'rtali piramida

int n = 5;

for (int i = 1; i <= n; i++) {
    // Bo'shliqlar
    for (int j = 1; j <= n - i; j++) {
        printf(" ");
    }
    // Yulduzlar
    for (int j = 1; j <= 2 * i - 1; j++) {
        printf("*");
    }
    printf("\n");
}

Natija:

    *
   ***
  *****
 *******
*********

11. for cheklov va o'zgaruvchilar

Bir nechta o'zgaruvchi

for (int i = 0, j = 10; i < j; i++, j--) {
    printf("i = %d, j = %d\n", i, j);
}

Natija:

i = 0, j = 10
i = 1, j = 9
i = 2, j = 8
i = 3, j = 7
i = 4, j = 6

Bo'sh qismlar

int i = 0;
for (; i < 10; ) {
    printf("%d ", i);
    i++;
}

Faqat condition — boshqalari bo'sh.

Cheksiz sikl

for (;;) {
    // Cheksiz! Faqat break bilan chiqadi
}

Yoki:

for (int i = 0; ; i++) {
    if (i >= 100) break;
    printf("%d ", i);
}

12. Eng katta umumiy bo'luvchi (GCD)

int a = 48, b = 18;
int gcd = 1;

for (int i = 1; i <= a && i <= b; i++) {
    if (a % i == 0 && b % i == 0) {
        gcd = i;
    }
}

printf("GCD(%d, %d) = %d\n", a, b, gcd);
// GCD(48, 18) = 6

13. Tub son tekshirish

Tub son (prime) — faqat 1 va o'ziga bo'linadigan raqam.

int n = 17;
int prime = 1;

for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
        prime = 0;
        break;
    }
}

if (n < 2) {
    prime = 0;
}

if (prime) {
    printf("%d — tub son\n", n);
} else {
    printf("%d — tub son emas\n", n);
}

14. Fibonacci ketma-ketligi

int n = 10;
int a = 0, b = 1;

printf("%d %d ", a, b);

for (int i = 2; i < n; i++) {
    int c = a + b;
    printf("%d ", c);
    a = b;
    b = c;
}
// 0 1 1 2 3 5 8 13 21 34

15. Common pitfalls

Off-by-one error

// XATO — 11 marta ishlaydi
for (int i = 0; i <= 10; i++) { ... }   // 0,1,2,...,10 (11 marta)

// To'g'ri — 10 marta
for (int i = 0; i < 10; i++) { ... }
for (int i = 1; i <= 10; i++) { ... }

Cheksiz sikl

// XATO — i hech qachon o'zgarmaydi
for (int i = 0; i < 10; ) {
    printf("%d ", i);
}
// Cheksiz aylanadi!

O'zgaruvchini ichkarida e'lon qilish

for (int i = 0; i < 10; i++) {
    int x = i * 2;
    printf("%d\n", x);
}

// printf("%d\n", x);  // XATO! x faqat for ichida ko'rinadi
// printf("%d\n", i);  // XATO! i ham

Increment to'g'ri

// XATO — i o'zgarmaydi (bu - operator emas)
for (int i = 0; i < 10; i+) { ... }

// To'g'ri
for (int i = 0; i < 10; i++) { ... }
for (int i = 0; i < 10; i += 1) { ... }

Darsdagi topshiriqlar

Topshiriq 1 — Asosiy for

asosiy.c — quyidagilarni chiqaring:

#include <stdio.h>

int main(void) {
    // 1 dan 20 gacha
    for (int i = 1; i <= 20; i++) {
        printf("%d ", i);
    }
    printf("\n");
    
    // 20 dan 1 gacha
    for (int i = 20; i >= 1; i--) {
        printf("%d ", i);
    }
    printf("\n");
    
    // Faqat juft (2 dan 50 gacha)
    for (int i = 2; i <= 50; i += 2) {
        printf("%d ", i);
    }
    printf("\n");
    
    // Faqat toq (1 dan 50 gacha)
    for (int i = 1; i <= 50; i += 2) {
        printf("%d ", i);
    }
    printf("\n");
    
    return 0;
}

Topshiriq 2 — Yig'indi va o'rtacha

sum.c:

#include <stdio.h>

int main(void) {
    int sum = 0;
    
    // 1+2+...+100
    for (int i = 1; i <= 100; i++) {
        sum += i;
    }
    printf("1 dan 100 gacha yig'indi: %d\n", sum);
    
    // 1+3+5+...+99 (toq)
    int sum_odd = 0;
    for (int i = 1; i <= 99; i += 2) {
        sum_odd += i;
    }
    printf("Toq yig'indi: %d\n", sum_odd);
    
    // 2*4*6*...*10
    int product = 1;
    for (int i = 2; i <= 10; i += 2) {
        product *= i;
    }
    printf("Juft ko'paytma: %d\n", product);
    
    return 0;
}

Topshiriq 3 — Faktorial

factorial.c — 1 dan 10 gacha barcha faktoriallarni chiqaring:

#include <stdio.h>

int main(void) {
    for (int n = 1; n <= 10; n++) {
        long fact = 1;
        for (int i = 1; i <= n; i++) {
            fact *= i;
        }
        printf("%d! = %ld\n", n, fact);
    }
    return 0;
}

Natija:

1! = 1
2! = 2
3! = 6
...
10! = 3628800

Topshiriq 4 — Ko'paytirish jadvali

mult-table.c — 9 ta ko'paytirish jadvali:

#include <stdio.h>

int main(void) {
    for (int i = 2; i <= 9; i++) {
        printf("\n=== %d ===\n", i);
        for (int j = 1; j <= 10; j++) {
            printf("%d * %d = %d\n", i, j, i * j);
        }
    }
    return 0;
}

Topshiriq 5 — Yulduzlar

stars.c — 4 ta naqsh:

#include <stdio.h>

int main(void) {
    int n = 5;
    
    // 1. Oddiy piramida
    printf("1) Oddiy piramida:\n");
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            printf("*");
        }
        printf("\n");
    }
    
    // 2. Teskari piramida
    printf("\n2) Teskari piramida:\n");
    for (int i = n; i >= 1; i--) {
        for (int j = 1; j <= i; j++) {
            printf("*");
        }
        printf("\n");
    }
    
    // 3. O'rtali piramida
    printf("\n3) O'rtali piramida:\n");
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n - i; j++) printf(" ");
        for (int j = 1; j <= 2 * i - 1; j++) printf("*");
        printf("\n");
    }
    
    // 4. To'rtburchak
    printf("\n4) To'rtburchak:\n");
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= 10; j++) {
            printf("*");
        }
        printf("\n");
    }
    
    return 0;
}

Topshiriq 6 — Tub sonlar

primes.c — 1 dan 100 gacha barcha tub sonlarni chiqaring:

#include <stdio.h>

int main(void) {
    printf("1 dan 100 gacha tub sonlar:\n");
    
    for (int n = 2; n <= 100; n++) {
        int prime = 1;
        
        for (int i = 2; i * i <= n; i++) {
            if (n % i == 0) {
                prime = 0;
                break;
            }
        }
        
        if (prime) {
            printf("%d ", n);
        }
    }
    printf("\n");
    
    return 0;
}

Topshiriq 7 — Fibonacci

fibonacci.c — birinchi 20 ta Fibonacci raqami:

#include <stdio.h>

int main(void) {
    int n = 20;
    long a = 0, b = 1;
    
    printf("%ld %ld ", a, b);
    
    for (int i = 2; i < n; i++) {
        long c = a + b;
        printf("%ld ", c);
        a = b;
        b = c;
    }
    printf("\n");
    
    return 0;
}

Topshiriq 8 — break va continue

break-continue.c:

#include <stdio.h>

int main(void) {
    // 1. break: 5'gacha
    printf("Break misol:\n");
    for (int i = 1; i <= 10; i++) {
        if (i == 5) break;
        printf("%d ", i);
    }
    printf("\n");
    
    // 2. continue: 5'ni o'tkazib yuborish
    printf("\nContinue misol:\n");
    for (int i = 1; i <= 10; i++) {
        if (i == 5) continue;
        printf("%d ", i);
    }
    printf("\n");
    
    // 3. Faqat tub
    printf("\nTub sonlar (break bilan):\n");
    for (int n = 2; n <= 20; n++) {
        int prime = 1;
        for (int i = 2; i < n; i++) {
            if (n % i == 0) {
                prime = 0;
                break;
            }
        }
        if (prime) printf("%d ", n);
    }
    printf("\n");
    
    return 0;
}

Topshiriq 9 — GCD va LCM

gcd-lcm.c:

#include <stdio.h>

int main(void) {
    int a = 48, b = 18;
    
    // GCD (eng katta umumiy bo'luvchi)
    int gcd = 1;
    for (int i = 1; i <= a && i <= b; i++) {
        if (a % i == 0 && b % i == 0) {
            gcd = i;
        }
    }
    printf("GCD(%d, %d) = %d\n", a, b, gcd);
    
    // LCM (eng kichik umumiy ko'paytuvchi)
    int lcm = (a * b) / gcd;
    printf("LCM(%d, %d) = %d\n", a, b, lcm);
    
    return 0;
}

Topshiriq 10 — GitHub'ga

bash

$ cd ~/c-darslari
$ mkdir 4-oy-dars-5
$ # fayllarni shu joyga
$ git add .
$ git commit -m "feat: dars 5 - for loops"
$ git push

Asosiy tushunchalar (lug'at)

Termin	Qisqacha izoh
Loop	Sikl, takrorlash
for	Asosiy sikl turi
Iteration	Sikl bir bor ishlashi
Init	Boshlash (`int i = 0`)
Condition	Shart (`i < 10`)
Update	Yangilanish (`i++`)
break	Sikldan chiqish
continue	Keyingi iteratsiyaga o'tish
Nested loop	Sikl ichida sikl
Off-by-one	1 ta xato (yana yoki kam)
Infinite loop	Cheksiz sikl
Factorial	n! = n(n-1)...*1
Fibonacci	0, 1, 1, 2, 3, 5, 8, ...
Prime	Tub son
GCD	Greatest Common Divisor
LCM	Lowest Common Multiple

Keyingi dars

6-dars: Sikllar — while, do-while →

5-dars: Sikllar — for ​

1. Sikl nima? ​

2. Nima uchun sikl? ​

3. for sikli tuzilmasi ​

Misol — 0 dan 9 gacha: ​

Qadamma-qadam ​

4. Asosiy for misollar ​

1 dan 10 gacha ​

Teskari: 10 dan 1 gacha ​

2 ga qadam ​

Toq raqamlar ​

5. Yig'indi hisoblash ​

6. O'rtacha hisoblash ​

7. Faktorial ​

8. Continue va Break ​

break — sikldan chiqish ​

continue — keyingi iteratsiyaga ​

9. Nested for — sikl ichida sikl ​

Ko'paytirish jadvali ​

10. Pattern (naqsh) chizish ​

Yulduzlar piramida ​

Teskari piramida ​

O'rtali piramida ​

11. for cheklov va o'zgaruvchilar ​

Bir nechta o'zgaruvchi ​

Bo'sh qismlar ​

Cheksiz sikl ​

12. Eng katta umumiy bo'luvchi (GCD) ​

13. Tub son tekshirish ​

14. Fibonacci ketma-ketligi ​

15. Common pitfalls ​

Off-by-one error ​

Cheksiz sikl ​

O'zgaruvchini ichkarida e'lon qilish ​

Increment to'g'ri ​

Darsdagi topshiriqlar ​

Asosiy tushunchalar (lug'at) ​

Keyingi dars ​

5-dars: Sikllar — for

1. Sikl nima?

2. Nima uchun sikl?

3. for sikli tuzilmasi

Misol — 0 dan 9 gacha:

Qadamma-qadam

4. Asosiy for misollar

1 dan 10 gacha

Teskari: 10 dan 1 gacha

2 ga qadam

Toq raqamlar

5. Yig'indi hisoblash

6. O'rtacha hisoblash

7. Faktorial

8. Continue va Break

break — sikldan chiqish

continue — keyingi iteratsiyaga

9. Nested for — sikl ichida sikl

Ko'paytirish jadvali

10. Pattern (naqsh) chizish

Yulduzlar piramida

Teskari piramida

O'rtali piramida

11. for cheklov va o'zgaruvchilar

Bir nechta o'zgaruvchi

Bo'sh qismlar

Cheksiz sikl

12. Eng katta umumiy bo'luvchi (GCD)

13. Tub son tekshirish

14. Fibonacci ketma-ketligi

15. Common pitfalls

Off-by-one error

Cheksiz sikl

O'zgaruvchini ichkarida e'lon qilish

Increment to'g'ri

Darsdagi topshiriqlar

Asosiy tushunchalar (lug'at)

Keyingi dars