{"id":682,"date":"2024-10-10T22:07:08","date_gmt":"2024-10-10T16:37:08","guid":{"rendered":"https:\/\/codexplained.in\/?p=682"},"modified":"2025-11-24T15:54:32","modified_gmt":"2025-11-24T10:24:32","slug":"find-prime-numbers-in-a-range","status":"publish","type":"post","link":"https:\/\/codexplained.in\/?p=682","title":{"rendered":"Find Prime Numbers in a Range."},"content":{"rendered":"
\n#include <stdio.h>\n\n\/\/ Function to check if a number is prime\nint isPrime(int num) {\n    if (num <= 1) return 0; \/\/ Numbers less than 2 are not prime\n    for (int i = 2; i * i <= num; i++) { \/\/ Check divisibility up to the square root of num\n        if (num % i == 0) return 0; \/\/ If divisible, it's not prime\n    }\n    return 1; \/\/ If not divisible, it's prime\n}\n\nint main() {\n    int start, end;\n\n    \/\/ Prompt user for input range\n    printf("Enter the starting number of the range: ");\n    scanf("%d", &start);\n    printf("Enter the ending number of the range: ");\n    scanf("%d", &end);\n\n    printf("Prime numbers between %d and %d are:\\n", start, end);\n\n    \/\/ Loop through the range and check for prime numbers\n    for (int num = start; num <= end; num++) {\n        if (isPrime(num)) {\n            printf("%d ", num); \/\/ Print the prime number\n        }\n    }\n    printf("\\n"); \/\/ New line after the list of prime numbers\n\n    return 0;\n}\n\n<\/pre><\/div>\n\n\n
Explanation of the Code<\/h2>\n\n\n\n
Loops through each number in the range and uses the isPrime<\/code> function to check if it’s prime. If it is, the number is printed.<\/p>\n\n\n\n
Header Files<\/strong>: The stdio.h<\/code> library is included for input and output functionalities.<\/p>\n\n\n\n
Function isPrime(int num)<\/code><\/strong>:<\/p>\n\n\n\n
Checks if a number is prime.<\/p>\n\n\n\n
Returns 0<\/code> for numbers less than or equal to 1 (not prime).<\/p>\n\n\n\n
Uses a loop to test for factors from 2<\/code> up to the square root of num<\/code>. If num<\/code> is divisible by any of these, it\u2019s not prime and returns 0<\/code>.<\/p>\n\n\n\n
If no factors are found, it returns 1<\/code>, indicating the number is prime.<\/p>\n\n\n\n
Main Function<\/strong>:<\/p>\n\n\n\n
Prompts the user for the starting and ending numbers of the range.<\/p>\n\n\n\n
Prints a header for the prime numbers found.<\/p>\n\n\n\n
Output<\/h2>\n\n\n\n
Enter the starting number of the range: 10\nEnter the ending number of the range: 30\nPrime numbers between 10 and 30 are:\n11 13 17 19 23 29<\/code><\/pre>\n