# C Programming: Find all prime factors of a given integer

## C Programming Mathematics: Exercise-35 with Solution

Write a C program that accepts an integer and find all prime factors of the integer.

Prime factors of a number are those factors that are prime numbers. 2 and 4 are factors of 4, where 2 is considered the prime factor.

**Test Data:**

(77) -> 7, 11

(12) -> 2, 2, 3

(45) -> 3, 3, 5

**Sample Solution:**

**C Code:**

```
#include <stdio.h>
#include <math.h>
int main(void) {
int n;
printf("Input an integer: ");
scanf("%d", &n); // Accepting an integer input
if (n > 0) { // Checking if the input is a positive number
// Dividing the number by 2 until it's odd and printing the factors of 2
while (n % 2 == 0) {
printf("2 ");
n /= 2;
}
// Loop to find and print factors starting from 3 up to the square root of 'n'
for (int i = 3; i <= sqrt(n); i += 2) { // Incrementing by 2 as even numbers are already factored by 2
while (n % i == 0) { // Check if 'i' is a factor of 'n'
printf("%d ", i); // Print the factor 'i'
n /= i; // Update 'n' by dividing with the factor 'i'
}
}
if (n > 2)
printf("%d", n); // If 'n' is greater than 2 and not fully factored, print it
}
}
```

Sample Output:

Input an integer: 78 2 3 13

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