# How to write a C program to find prime factors of an integer number

Prime factors

The factors of a number which are prime are called prime factors

example prime factors of integer 6 are 2 & 3 similarly prime factors of integer 8 are: 2

1>write a program in c to generate prime factors of an integer number using for loop

write a program to generate prime factors of an integer number using for loop using c programming

#include<stdio.h>

#include<conio.h>

void main()

{

int n,i,j,c ; // c is flag

clrscr();

printf(“To generate prime factors of an integer number”);

printf(“Enter Number:”);

scanf(“%d”,&n);

printf(“\n\n The Prime Factors of number %d are: “,n);

for(i=2;i<=n;i++) // for finding factors

{

if(n%i==0)

{

for(j=2;j<i;j++) // for finding prime number in factors

{

if i%j==0:

{

c =0;

break;

}

else

c =1;

} //for end

if (c==1)

printf(“\t %d,”,i);

} //end of if

} // end of for

getch();

}

OUTPUT:

To generate prime factors of an integer number

Enter number:12

Prime factors of number 6 are 2 3

RUN2

To generate prime factors of an integer number

Enter a number:15

Prime factors of number 15 are 3 5

2>WAP to find prime factors of an integer number using while loop

WAP to find prime factors of an integer number using while loop in c

#include<stdio.h>

#include<conio.h>

void main()

{

int no,i=2,j=2,c; // c is flag value

clrscr();

printf(“To find prime factors of an integer number \n”);

printf(“Enter a Number:”);

scanf(“%d”,&no);

printf(“\n Prime Factors of integer number %d are: “,n);

while(i<=no) // for finding factors

{

if(no%i==0)

{

while(j<i) // for finding prime number in factors

{

if( i%j==0:)

c =0;

break;

else

c =1;

j++;

}

if (c==1)

printf(“\t %d,”,i);

}

i++;

}

getch();

}

OUTPUT:

To find prime factors of an integer number

Enter a number:16

The Prime factors of integer number 16 are: 2

3>write a C program to find sum of prime factors of an integer number using c programming

write a program to find sum of prime factors of an integer number using c programming

#include<stdio.h>

#include<conio.h>

void main()

{

int num,i=2,j=2,c; // c is flag

clrscr();

printf(“To find sum prime factors of an integer number \n”);

printf(“Enter a Number:”);

scanf(“%d”,&num);

printf(“\n prime factors of integer %d are: “,n);

while(i<=num) // for finding factors

{

if(num%i==0)

{

while(j<i) // for finding prime number in factors

{

if( i%j==0:)

c =0;

break;

else

c=1;

j++;

}

if ( c ==1)

printf(“\t %d,”,i);

sum=sum+i; // sum of prime factors

}

i++;

}

printf(“Sum of prime factors of %d is %d,”,num, sum);

getch();

}

OUTPUT:

To find sum of prime factors of an integer

Enter a number:12

Prime factors of integer 12 are: 2 3

Sum of prime factors of 12 is 5

RUN2:

To find sum of prime factors of an integer

Enter a number:15

Prime factors of integer 15 are: 3 5

Sum of prime factors of 15 is 8