Factorization

#include <stdio.h>

int factor(int n){
   int p, flag;
   flag = 0;
   p=2;
    while (p*p <= n) {
    if (n % p == 0) {
    flag = 1;
    return(p);
    break;
    }
    else
    p=p+1;
    }
    if(flag == 0)
      return(n);
}
   
int main() {
int n, fact;
   printf("Input a number > ");
   scanf("%d",&n);
   printf("Prime factors of %d are: ",n);
   do {
   fact = factor(n);
   printf("%d  ",fact);
   n = n/fact;
   } while(n != 1);
   printf("\n");
}

Finding zeros of functions

Bisection Method

/* bisection.c */

#include <stdio.h>

#define epsilon 0.0000001

double f (double x) {
   return (x*x - 3) ;
}

int main() {

double L,M,R;

printf("Enter the left (L) and right (R) end of the interval\n");
printf("where the zero lies: ");
scanf("%lf %lf", &L, &R);
printf(" [%lf,%lf]\n",L,R);

if (f(L)*f(R) > 0) 
   printf(" No sign change ... exit!\n");
else {
	do {
              M = (L+R)/2.0;
       if (f(L)*f(M) > 0)
            L = M;
       else 
            R = M;
           printf(" [%lf,%lf]\n",L,R);
         } while(R-L > epsilon);
       printf("A zero is equal %lf\n",L);
     }
}