C Programming Codes

#CProgramming #BitwiseOperations

Set/Clear/Toggle Bits

#include <stdio.h>

int main() {
    unsigned int num = 10; // Example number
    int bit_position = 1; // Example bit position (0-indexed)

    // Set bit
    unsigned int set_mask = 1 << bit_position;
    unsigned int set_result = num | set_mask;
    printf("Number after setting bit %d: %u\n", bit_position, set_result);

    // Clear bit
    unsigned int clear_mask = ~(1 << bit_position);
    unsigned int clear_result = num & clear_mask;
    printf("Number after clearing bit %d: %u\n", bit_position, clear_result);

    // Toggle bit
    unsigned int toggle_mask = 1 << bit_position;
    unsigned int toggle_result = num ^ toggle_mask;
    printf("Number after toggling bit %d: %u\n", bit_position, toggle_result);

    return 0;
}

#Cprogramming #BitManipulation #InterviewQuestion

Check if Nth Bit is Set

#include <stdio.h>
#include <stdint.h>

int isNthBitSet(uint32_t num, int n) {
    if (n < 0 || n >= 32) {
        return -1; 
    }
    return (num & (1UL << n)) != 0;
}

int main() {
    uint32_t number = 10; 
    int n = 1;          
    int result = isNthBitSet(number, n);

    if (result == -1) {
        printf("Invalid bit position\n");
    } else if (result) {
        printf("Bit %d is set in %u\n", n, number);
    } else {
        printf("Bit %d is not set in %u\n", n, number);
    }

    return 0;
}

#CProgramming #BitManipulation #KernighanAlgorithm

Count Set Bits (Brian Kernighan's Algorithm)

#include <stdio.h>

int countSetBits(int n) {
    int count = 0;
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}

int main() {
    int num = 9;
    printf("Number of set bits in %d is %d\n", num, countSetBits(num));
    return 0;
}

#CProgramming #BitManipulation #Algorithm #InterviewQuestion #Kernighan

Count Set Bits (Brian Kernighan's Algorithm)

#include <stdio.h>

int countSetBits(int n) {
    int count = 0;
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}

int main() {
    int num = 9; 
    printf("Number of set bits in %d is %d\n", num, countSetBits(num));
    return 0;
}

#CProgramming #SwapNumbers #WithoutTemp #InterviewQuestion #ArithmeticSwap

Swap Two Numbers Without Temp

#include <stdio.h>

int main() {
    int a = 5;
    int b = 10;
    a = a + b;
    b = a - b;
    a = a - b;
    printf("a = %d, b = %d\n", a, b);
    return 0;
}

#CProgramming #CLanguage #DSA #InterviewPrep #SwapLogic

Swap Two Numbers Without Temp

#include <stdio.h>

int main() {
    int a = 5;
    int b = 10;
    a = a + b;
    b = a - b;
    a = a - b;
    printf("a = %d, b = %d\n", a, b);
    return 0;
}

#CProgramming #CLanguage #DSA #InterviewPrep #SwapLogic

Swap Two Numbers Without Temp

#include <stdio.h>

int main() {
    int a = 5;
    int b = 10;
    a = a + b;
    b = a - b;
    a = a - b;
    printf("a = %d, b = %d\n", a, b);
    return 0;
}

#CPP #BitManipulation #BrianKernighan

Count Set Bits (Brian Kernighan's Algorithm)

#include <iostream>

using namespace std;

int countSetBits(int n) {
    int count = 0;
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}

int main() {
    int num = 7; 
    cout << "Number of set bits in " << num << " is " << countSetBits(num) << endl;
    return 0;
}

#CProgramming #BitwiseOperators #SwapTechnique

Swap Two Numbers using XOR

#include <stdio.h>

void swap(int *x, int *y) {
    *x = *x ^ *y;
    *y = *x ^ *y;
    *x = *x ^ *y;
}

int main() {
    int a = 10, b = 5;
    swap(&a, &b);
    printf("a = %d, b = %d\n", a, b);
    return 0;
}

#CProgramming #Combinations #nCr

Find nCr (Combinations)

#include <stdio.h>

long long factorial(int n) {
    if (n == 0)
        return 1;
    else
        return n * factorial(n - 1);
}

long long nCr(int n, int r) {
    if (r < 0 || r > n)
        return 0;
    if (r == 0 || r == n)
        return 1;
    if (r > n / 2)
        r = n - r;
    return factorial(n) / (factorial(r) * factorial(n - r));
}

int main() {
    int n, r;
    printf("Enter n and r: ");
    scanf("%d %d", &n, &r);
    printf("nCr = %lld\n", nCr(n, r));
    return 0;
}