### Thread: listing numbers in columns

1. No Profile Picture
Junior Member
Devshed Newbie (0 - 499 posts)

Join Date
Aug 2003
Location
Gold Coast, Australia
Posts
5
Rep Power
0

#### listing numbers in columns

i need to list numbers in a table 10 colums wide. It is not working properly.... Any clues?

#include <stdio.h>

#define PRIME_MAX 10000
#define NUM_MAX 9

int main() {
int i;
int j;
bool prime[PRIME_MAX];
int num[NUM_MAX];
int counter;
prime[PRIME_MAX] = i;
num[NUM_MAX] = j;

printf("\n Prime numbers from 1 to %d\n", PRIME_MAX);
printf("\n");

counter = 0;

for (i = 0; i < PRIME_MAX; i++) {
prime[i] = true;
for (j = 2; j < NUM_MAX; j++) {
if ((j < i) && (i % j == 0)) {
prime[i] = false;
}
}
if (prime[i] == true) {
printf("%6d%c", i, (i + 1) % 10 == 0 ? '\n' : ' ');
counter = counter + 1;
}
}

printf("\n");
printf("Total prime numbers less than %d: %d\n", PRIME_MAX, counter);
}
2. No Profile Picture
Junior Member
Devshed Newbie (0 - 499 posts)

Join Date
Aug 2003
Posts
14
Rep Power
0
Not that I wanted to do your work for you, but...

#include <stdio.h>

#define PRIME_MAX 10000
#define NUM_MAX 9

int main() {
bool prime;

printf("\n Prime numbers from 1 to %d\n\n", PRIME_MAX);

int total = 0;

for (int i = 0; i < PRIME_MAX; i++) {
prime = true;
for (int j = i-1; j > 1; j--) {
if (i % j == 0) {
prime = false;
}
}
if (prime == true) {
printf("%6d%c", i, (total + 1) % 10 == 0 ? '\n' : ' ');
total++;
}
}

printf("\n");
printf("Total prime numbers less than %d: %d\n", PRIME_MAX, total);
}

Some things to note... your column was testing the current "i" not the total primes that you have output. Also, unless I'm mistaken (which I might be since it's early and I'm very tired) prime numbers are only divisible by 1 and themselves... so that check had to be modified.

Anyway, I hope this helps.
3. No Profile Picture
Junior Member
Devshed Newbie (0 - 499 posts)

Join Date
Aug 2003
Location
Gold Coast, Australia
Posts
5
Rep Power
0
thanks, that worked beautifully.