# Program to find Prime Numbers Between given Interval

Given two numbers and as interval range, the task is to find the prime numbers in between this interval.

Examples:

```Input : a = 1, b = 10
Output : 2, 3, 5, 7

Input : a = 10, b = 20
Output : 11, 13, 17, 19
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

In the below program, the range of numbers is taken as input and stored in the variables ‘a’ and ‘b’. Then using for-loop, the numbers between the interval of a and b are traversed. For each number in the for loop, it is checked if this number is prime or not. If found prime, print the number. Then the next number in the loop is checked, till all numbers are checked.

Program:

## C

 `// C program to find the prime numbers ` `// between a given interval ` ` `  `#include ` ` `  `int` `main() ` `{ ` `    ``// Declare the variables ` `    ``int` `a, b, i, j, flag; ` ` `  `    ``// Ask user to enter lower value of interval ` `    ``printf``(``"Enter lower bound of the interval: "``); ` `    ``scanf``(``"%d"``, &a); ``// Take input ` ` `  `    ``// Ask user to enter upper value of interval ` `    ``printf``(``"\nEnter upper bound of the interval: "``); ` `    ``scanf``(``"%d"``, &b); ``// Take input ` ` `  `    ``// Print display message ` `    ``printf``(``"\nPrime numbers between %d and %d are: "``, a, b); ` ` `  `    ``// Traverse each number in the interval ` `    ``// with the help of for loop ` `    ``for` `(i = a; i <= b; i++) { ` `        ``// Skip 1 as1 is niether ` `        ``// prime nor composite ` `        ``if` `(i == 1) ` `            ``continue``; ` ` `  `        ``// flag variable to tell ` `        ``// if i is prime or not ` `        ``flag = 1; ` ` `  `        ``for` `(j = 2; j <= i / 2; ++j) { ` `            ``if` `(i % j == 0) { ` `                ``flag = 0; ` `                ``break``; ` `            ``} ` `        ``} ` ` `  `        ``// flag = 1 means i is prime ` `        ``// and flag = 0 means i is not prime ` `        ``if` `(flag == 1) ` `            ``printf``(``"%d "``, i); ` `    ``} ` ` `  `    ``return` `0; ` `} `

## Java

 `import` `java.util.Scanner; ` ` `  `// Java program to find the prime numbers  ` `// between a given interval  ` `public` `class` `GFG { ` ` `  `// driver code  ` `    ``public` `static` `void` `main(String[] args) { ` `        ``Scanner sc = ``new` `Scanner(System.in); ` `        ``// Declare the variables  ` `        ``int` `a, b, i, j, flag; ` ` `  `        ``// Ask user to enter lower value of interval  ` `        ``System.out.printf(``"Enter lower bound of the interval: "``); ` `        ``a = sc.nextInt(); ``// Take input  ` ` `  `        ``// Ask user to enter upper value of interval  ` `        ``System.out.printf(``"\nEnter upper bound of the interval: "``); ` `        ``b = sc.nextInt(); ``// Take input  ` ` `  `        ``// Print display message  ` `        ``System.out.printf(``"\nPrime numbers between %d and %d are: "``, a, b); ` ` `  `        ``// Traverse each number in the interval  ` `        ``// with the help of for loop  ` `        ``for` `(i = a; i <= b; i++) { ` `            ``// Skip 1 as1 is niether  ` `            ``// prime nor composite  ` `            ``if` `(i == ``1``) { ` `                ``continue``; ` `            ``} ` ` `  `            ``// flag variable to tell  ` `            ``// if i is prime or not  ` `            ``flag = ``1``; ` ` `  `            ``for` `(j = ``2``; j <= i / ``2``; ++j) { ` `                ``if` `(i % j == ``0``) { ` `                    ``flag = ``0``; ` `                    ``break``; ` `                ``} ` `            ``} ` ` `  `            ``// flag = 1 means i is prime  ` `            ``// and flag = 0 means i is not prime  ` `            ``if` `(flag == ``1``) { ` `             ``System.out.println(i);  ` `            ``} ` ` `  `        ``} ` `    ``} ` `} `

## Python3

# Python3 program to find the prime
# numbers between a given interval

if __name__ == ‘__main__’:

# Declare the variables
a, b, i, j, flag = 0, 0, 0, 0, 0

# Ask user to enter lower value of interval
print(“Enter lower bound of the interval:”,
end = “”)
a = int(input()) # Take input
print(a)

# Ask user to enter upper value of interval
print(“Enter upper bound of the interval:”,
end = “”)
b = int(input()) # Take input
print(b)

# Print display message
print(“Prime numbers between”, a, “and”,
b, “are:”, end = “”)

# Traverse each number in the interval
# with the help of for loop
for i in range(a, b + 1):

# Skip 1 as1 is niether
# prime nor composite
if (i == 1):
continue

# flag variable to tell
# if i is prime or not
flag = 1

for j in range(2, i // 2 + 1):
if (i % j == 0):
flag = 0
break

# flag = 1 means i is prime
# and flag = 0 means i is not prime
if (flag == 1):
print(i, end = ” “)

# This code is contributed
# by Mohit kumar 29

Output:

```Enter lower bound of the interval: 1
Enter upper bound of the interval: 10
Prime numbers between 1 and 10 are: 2 3 5 7
```

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