C Programming Language || Hands On Coding

#include <iostream>
using namespace std;
int fibonacci(int n) {
    int a = 0, b = 1, temp;
    if (n == 0) return a;
    for (int count = 2; count <= n; count++) {
        temp = b;
        b = a + b;
        a = temp;
    }
    return b;
}
int main() {
    int n;
    cout << "Enter the value of n: ";
    cin >> n;
    cout << n << "th Fibonacci number is: " << fibonacci(n) << endl;
    return 0;
}

#include <iostream>
using namespace std;
int fibonacci(int n) {
    int a = 0, b = 1, temp;
    if (n == 0) return a;
    for (int count = 2; count <= n; count++) {
        temp = b;
        b = a + b;
        a = temp;
    }
    return b;
}
int main() {
    int n;
    cout << "Enter the value of n: ";
    cin >> n;
    cout << n << "th Fibonacci number is: " << fibonacci(n) << endl;
    return 0;
}

#include <iostream>
using namespace std;


void checkCase(char ch) {
    if(ch >= 'a' && ch <= 'z'){
        cout << "Entered character is in lower case" << endl;
    }
    else if(ch >= 'A' && ch <= 'Z'){
        cout << "Entered character is in upper case" << endl;
    }
    else{
        cout << "Invalid character entered" << endl;
    }
}

int main() {
    cout << "Enter any character: ";
    char ch;
    cin >> ch;
    checkCase(ch);
    return 0;
}

#include <iostream>
using namespace std;

int largestOfThree(int a, int b, int c) {
    int largest = a;
    if(b > largest)
        largest = b;
    if(c > largest)
        largest = c;
    return largest;
}

int main() {
    int first, second, third;
    cout << "Enter any three numbers: ";
    cin >> first >> second >> third;
    
    int large = largestOfThree(first, second, third);
    cout << "Largest number among " << first << ", " << second << ", " 
         << third << " is: " << large << endl;
    
    return 0;
}

cpp
#include <iostream>
using namespace std;

int area(int side) {
    return side * side;
}

int area(int length, int breadth) {
    return length * breadth;
}

int main() {
    int side,length,breadth;
    cout << "Enter a side length of a square:" << endl;
    cin >> side;
    cout << "Enter length and breadth of rectangle:" << endl;
    cin >> length >> breadth;
    cout << "Area of square: " << area(side) << endl;         
    cout << "Area of rectangle: " << area(length, breadth) << endl;    
    return 0;
}

#include <iostream>
using namespace std;

void passByReference(int& x) {
    x = 20;  
}

int main() {
    int a = 10;
    cout << "Value of a before function call: " << a << endl; 
    passByReference(a);
    cout << "Value of a after function call: " << a << endl; 
    return 0;
}

#include <iostream>
using namespace std;

void passByValue(int x) {
    x = 20;  
}

int main() {
    int a = 10;
    cout << "Value of a before function call: " << a << endl;  
    passByValue(a);
    cout << "Value of a after function call: " << a << endl;  
    return 0;
}

#include <iostream>

using namespace std;
int findMax(int n1 , int n2){
    if(n1 > n2){
        return n1;
    }
    return n2;
}

int main() {
     int num1,num2;
     cout << "Enter any two different numbers:"<<endl;
     cin >> num1 >> num2;
     int max = findMax(num1,num2);
     cout << "Maximum of "<< num1 << " and " << num2 << " is " << max;
     return 0;
}

#include <iostream>

using namespace std;

int main() {
    int n,sum=0,i=1;
    cout << "Enter the value of n:";
    cin >> n;
    do{
        sum = sum + i;
        i++;
    }while(i <= n);
    cout << "Sum of "<< n << " natural numbers :" << sum;
}

#include <iostream>

using namespace std;

int main()
{
    int numberToGuess = 4;
    int attempts = 0;
    int guess;
    while (guess != numberToGuess)
    {
        cout << "Guess the number between 0 and 9:" << endl;
        cin >> guess;
        attempts++;
        if(guess == numberToGuess){
            cout << "You guessed it right in " << attempts << " attempts" << endl;
        }
    }
    cout << "Game ended";
    return 0;
}

cpp
#include <iostream>

using namespace std;

int main(){
    int numbers[] = {11,12,13,14,15};
    int sum = 0;
    for(int number : numbers){
        sum = sum + number;
    }
    cout << "Sum = "<< sum;
    return 0;
}

cpp
#include <iostream>

using namespace std;

int main() {
    int num,res=1;
    cout << "Enter a positive number:" << endl;
    cin >> num;
    if(num < 0){
        cout << "You entered a negative number" << endl;
    }
    else if(num == 0){
        cout << "0! = " << "1";
    }
    else{
        for(int i = 1;i <= num;i++){
            res = res * i;
        }
        cout << "Factorial of " << num << " is "<<res;
    }

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    char op;
    double num1, num2;
    cout << "Enter an operator (+, -, *, /): ";
    cin >> op;

    cout << "Enter two numbers: ";
    cin >> num1 >> num2;

    switch (op) {
        case '+': cout << "Result: " << num1 + num2 << endl; break;
        case '-': cout << "Result: " << num1 - num2 << endl; break;
        case '*': cout << "Result: " << num1 * num2 << endl; break;
        case '/': 
            if (num2 != 0)
                cout << "Result: " << num1 / num2 << endl;
            else
                cout << "Error! Division by zero." << endl;
            break;
        default: cout << "Invalid operator!" << endl;
    }

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int year;
    cout << "Enter a year: ";
    cin >> year;

    if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
        cout << year << " is a Leap Year." << endl;
    else
        cout << year << " is not a Leap Year." << endl;

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int a, b, c;
    cout << "Enter three numbers: ";
    cin >> a >> b >> c;

    if (a >= b && a >= c)
        cout << "Largest number is: " << a << endl;
    else if (b >= a && b >= c)
        cout << "Largest number is: " << b << endl;
    else
        cout << "Largest number is: " << c << endl;

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;

    if (num % 2 == 0)
        cout << num << " is Even." << endl;
    else
        cout << num << " is Odd." << endl;

    return 0;
}

#include <iostream>
using namespace std;

int main() {
    char op;
    double num1, num2;
    cout << "Enter an operator (+, -, *, /): ";
    cin >> op;

    cout << "Enter two numbers: ";
    cin >> num1 >> num2;

    switch (op) {
        case '+': cout << "Result: " << num1 + num2 << endl; break;
        case '-': cout << "Result: " << num1 - num2 << endl; break;
        case '*': cout << "Result: " << num1 * num2 << endl; break;
        case '/': 
            if (num2 != 0)
                cout << "Result: " << num1 / num2 << endl;
            else
                cout << "Error! Division by zero." << endl;
            break;
        default: cout << "Invalid operator!" << endl;
    }

    return 0;
}