Quick Revision

#include <stdio.h>

int main()
{
    // Variable declarations
    int n, temp;

    // Input
    printf("Enter value ->");
    scanf("%d", &n);

    // Processing
    // ...

    // Output
    printf("Result is %d", result);

    return 0;
}

// Array declaration and input
int arr[n];
printf("Enter %d numbers->", n);
for (int i = 0; i < n; i++)
{
    scanf("%d", &arr[i]);
}

// Array traversal
for (int i = 0; i < n; i++)
{
    printf("%d ", arr[i]);
}

// Pointer declaration and assignment
int *p = &arr[j];
int *p = arr;  // points to first element

// Pointer dereferencing
if (*p > *(p + 1))
{
    temp = *p;
    *p = *(p + 1);
    *(p + 1) = temp;
}

// Accessing elements via pointer
largest = *(p + n - 1);
smallest = *p;

// For loop - known iterations
for (int i = 0; i < n; i++)
{
    // process arr[i]
}

// Nested loops - sorting
for (int i = 0; i < n - 1; i++)
{
    for (int j = 0; j < n - 1 - i; j++)
    {
        // bubble sort logic
    }
}

// While loop - unknown iterations
while (test != 0)
{
    // process until condition
    test /= 10;
}

// Simple if-else
if (count == 2)
{
    printf("Prime\n");
}
else
{
    printf("Not Prime\n");
}

// Multiple conditions
if (num == 1 || num <= 0)
{
    printf("Invalid input\n");
}
else if (count == 2)
{
    printf("Prime\n");
}
else
{
    printf("Not Prime\n");
}

// File opening and reading
FILE *file;
file = fopen("filename.txt", "r");

if (file != NULL)
{
    while (fscanf(file, "%d", &x) == 1)
    {
        // process each number
    }
    fclose(file);
}

// String length calculation
int length = 0;
while (str[length] != '\n')
{
    length++;
}

// String palindrome check
for (int i = 0; i < length; i++)
{
    if (str[i] != str[length - 1 - i])
    {
        count = 1;
        break;
    }
}

// Prime check
int count = 0;
for (int j = 1; j <= num; j++)
{
    if (num % j == 0)
    {
        count++;
    }
}
if (count == 2) // prime

// Sum of digits
int sum = 0;
while (temp != 0)
{
    sum += temp % 10;
    temp /= 10;
}

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

// Multiple inputs
scanf("%d %d", &a, &b);

// Array input with prompt
printf("Enter %d numbers->", n);
for (int i = 0; i < n; i++)
{
    scanf("%d", &arr[i]);
}

// Formatted output
printf("Largest is %d and smallest is %d", largest, smallest);