Prime number array program c

As you can see in the above code we have taken two for loops because we need a list of prime numbers that will be below the given number in our program. We have included for loop within another for loop to make our calculation easier. A condition is added through if statement to break the loop once we reach our given number in code.

In the above code, we have taken integers as a lower number, higher number, temporary variable, and a flag. Initially, we take two numbers as an input one is lower while the other is higher.

In case the lower number is bigger than the higher number then these numbers will be swapped through a temporary variable first to move further in code. Now while loop will follow up until lower is less than higher and for loop, the condition will keep calculating prime numbers between them. From a small set of numbers to a big amount of numbers this logic can be used to find a set of prime numbers according to requirements within seconds without wasting any time in computer programming.

Here, we have used a for loop to take 5 inputs from the user and store them in an array. Then, using another for loop, these elements are displayed on the screen. Now let's say if you try to access testArray[12]. The element is not available. This may cause unexpected output undefined behavior. Sometimes you might get an error and some other time your program may run correctly. In the next tutorial, you will learn about multidimensional arrays array of an array.

Course Index Explore Programiz. Popular Tutorials Data Types in C. C for Loop. Arrays in C Programming. Pointers in C. Find roots of a quadratic equation. Print Pyramids and Patterns. The function is calling itself recursively n times until either a factor is found or one of the conditions is satisfied. Therefore, the time complexity is O n.

The n calls made by the recursive function will be stored in the stack which will consume space in the memory. Therefore, the space complexity of the recursive approach will be O n. In the above program, we have used an optimized solution to check if a number is prime or not. This is because the smallest factor of a number greater than 1 can not be greater than the square root of the number.

No extra space is being used in the program. Only a constant auxiliary space is used to store variables and iteration is done in place. In the above program, we are printing the sum of the prime numbers in the given range.

The starting and ending points are being read by the user. We have iterated a nested for loop. STEP 2: Create a boolean array isPrime[] and initialize all its elements to 1 assuming initially all elements are prime. The above approach is based upon the sieve of Eratosthenes. We have defined an array of the boolean type whose all elements are initially true.

True means we have supposed that initially, all the elements are prime. If a number is updated as false, then it will not be a prime number.

We have iterated a loop starting from 2 that will mark all the multiples of 2 which are greater than or equal to its square up to num as false.

After this, the elements that remain unmarked or true will all be the prime numbers. Email Required, but never shown. The Overflow Blog. Stack Gives Back Safety in numbers: crowdsourcing data on nefarious IP addresses. Featured on Meta. New post summary designs on greatest hits now, everywhere else eventually. Related Hot Network Questions. Question feed.