 # C Program to Find Prime Factors of a Number

C program to find prime factors of a number; Through this tutorial, we will learn how to find and print prime factors of a number in the c program using for loop, while loop, and recursion.

## Programs to Find Prime Factors of a Number in C

• C Program to Find Prime Factors of a Number Using For Loop
• C Program to Find Prime Factors of a Number Using While Loop
• C Program to Find Prime Factors of a Number Using Recursion

### C Program to Find Prime Factors of a Number Using For Loop

```/* C Program to Find Prime Factors of a Number using For Loop */

#include <stdio.h>

int main()
{
int i, j, Number, isPrime;

printf("\n Please Enter any number to Find Factors :  ");
scanf("%d", &Number);

for (i = 2; i <= Number; i++)
{
if(Number % i == 0)
{
isPrime = 1;
for (j = 2; j <= i/2; j++)
{
if(i % j == 0)
{
isPrime = 0;
break;
}
}
if(isPrime == 1)
{
printf("\n %d is a Prime Factor ", i);
}
}
}
return 0;
}
```

The output of the above c program; as follows:

```Please Enter any number to Find Factors :  20
2 is a Prime Factor
5 is a Prime Factor ```

### C Program to Find Prime Factors of a Number Using While Loop

```/* C Program to Find Prime factors of a Number using While Loop */

#include <stdio.h>

int main()
{
int Number, i = 1, j, Count;

printf("\n Please Enter number to Find Factors  :  ");
scanf("%d", &Number);

while (i <= Number)
{
Count = 0;
if(Number % i == 0)
{
j = 1;
while(j <= i)
{
if(i % j == 0)
{
Count++;
}
j++;
}
if(Count == 2)
{
printf("\n %d is a Prime Factor ", i);
}
}
i++;
}

return 0;
}
```

The output of the above c program; as follows:

```Please Enter number to Find Factors  :  50
2 is a Prime Factor
5 is a Prime Factor ```

### C Program to Find Prime Factors of a Number Using Function

```#include <stdio.h>

void Find_Prime(int Number)
{
int i, Count = 0;

for (i = 2; i <= Number/2; i++)
{
if(Number%i == 0)
{
Count++;
}
}
if(Count == 0 && Number != 1 )
{
printf("\n %d is a Prime Number", Number);
}
}
void Find_Factors(int Number)
{
int i;

for (i = 1; i <= Number; i++)
{
if(Number % i == 0)
{
// Calling Find_Prime Function for every factor
Find_Prime(i);
}
}
}
int main()
{
int i, j, Number, count;

printf("\n Please Enter any number to Find it's Prime Factors :  ");
scanf("%d", &Number);

printf("\n Prime Factors of a Given Number are : \n");
Find_Factors(Number);

return 0;
}
```

The output of the above c program; as follows:

```Please Enter any number to Find it's Prime Factors :  100
Prime Factors of a Given Number are :

2 is a Prime Number
5 is a Prime Number```

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