Thread: can someone help with an array

I am trying to have a user enter 5 numbers and store them in an array and then have the user enter an additional number and multiply the 5 numbers by it. But I can't get even get an array to accept 5 numbers. Can someone please help,

code:
#include <stdio.h>
#include <stdlib.h>

#define N 5

int main(void)
{
int a[N];
int i, sum=0, factor;

printf("\nPlease enter 5 numbers\n");
for (i=0;i<N; ++i);
a[i]=0+i*i;
printf("\nPlease enter a factor:\t");
scanf("%d",&factor);





return 0;
}

This should allow you to accept 5 numbers.

Code:

#include <stdio.h> 
#include <stdlib.h>

#define N 5

int main(void)
{
int a[N];
int i, sum=0, factor;

printf("\nPlease enter 5 numbers\n");
for (i=0;i<N; ++i);
{
  printf("Number %d: ", i+1);
  scanf("%d", &a[i])
}

printf("\nPlease enter a factor:\t");
scanf("%d",&factor);

return 0;
}

Look at my example:

Code:

#include <stdio.h>
#include <stdlib.h>

#define SIZE 5 /* size of array */

int main(void)
{
    int i, factor, arr[SIZE];
    
    /* get the numbers */
    for (i=0; i<SIZE; ++i)
      scanf("%d",&arr[i]);
    
    /* get the factor */
    printf("Insert the factor: ");
    scanf("%d",&factor);
    
    /* multiply all them by factor */
    for (i=0; i<SIZE; ++i)
      arr[i] *= factor;
      
    /* display array */
    for (i=0; i<SIZE; ++i)
       printf("%d ",arr[i]);
    
    /* pause */
    system("PAUSE");
    
    /* exit */
    return 0;
}

You have some problems in your code, like here:

Code:

for (i=0;i<N; ++i);

In this case you dont need to ; the for command, you just need to close it when you want a null loop.

Cool thanks that helps. I have never been good at arrays. C programming is kind of new to me. It makes more sense now.

After multiplication are the new numbers automatically stored in the Array or do I need to put them in there somehow?

Cool..... I wrote this piece to sum the the array and it works but I only want to carry out 2 decimal places and I have like 6.

Code:

	/*sum the array*/
	sum=0;
	for (i=0; i<SIZE; ++i)
		sum +=(SIZE+i);
	printf("\nThis is the sum of the new Array values: %f\n", sum);

I added a line to try to calculate the average but it doesn't come put right. If I enter 1,2,3,4,5 in the array and a factor of 2 the array returns 2,4,6,8,10 like it should but when I divide by 5 it comes up with 7.

Code:

	/*sum the array and calculate average*/
	sum=0;
	average=0;
	for (i=0; i<SIZE; ++i)
		sum +=(SIZE+i);
		average = (sum/5);
	printf("\nThe average of the new Array values is: %f\n", average);

I must be doing something wring in this code because it totals the values wrong.

Code:

	/*sum the array and calculate average*/
	sum=0;
	average=0;
	for (i=0; i<SIZE; ++i)
		sum +=(SIZE+i);
		average = (sum/5);
	printf("\nThe average of the new Array values is: %.2f\n", sum);

I think I just fixed it. This is what I did.

Code:

	sum=0;
	average=0;
	for (i=0; i<SIZE; ++i)
		sum += arr[i];
		average = (sum/5);
	printf("\nThe average of the new Array values is: %.2f\n", average);