While loop with user input validation to fill array, then search array for largest number.

Question

I am working on a program that will accept user input to fill an array and then quit when the user enters q. Next the array is passed to a function that finds the largest value in the array. My program seems like it would work, but I believe that user input for the array is incorrect and I am not sure how to solve it.

#include <stdio.h>
#define SIZE 30

int maxnum(int userarray[], int maxx);


int main()
{
    int i;
    int nums[SIZE];
    int largest;


    printf("Type integer numbers (up to 30), followed by q to quit:\n");

    while(scanf("%d", &nums[i]) == 1)
    {
        for(i = 0; i < SIZE; i++)
        {
            //blank
        }
    }

    largest = maxnum(nums, SIZE);
    printf("The largest number is: %d\n", largest);

    return 0;
}

int maxnum(int userarray[], int maxx)
{
    int i;
    int maxnumber; 

    maxnumber = userarray[0];

    for(i = 1; i < maxx; i++)
    {
        if(maxnumber < userarray[i])
        {
            maxnumber = userarray[i];
        }
    }

    return maxnumber; 
}

Jean-François Fabre · Accepted Answer · 2016-10-15 07:43:48Z

3

First i is unitialized.

Then your inner for loop is strange (why someone would do that??) and sets i to SIZE in the end, which is not good.

I don't give more details, but the value of i is trash all the time because of those 2 mistakes it should be:

int i = 0;

while((i<SIZE) && (scanf("%d", &nums[i]) == 1))
{
    i++;
}

so you read one by one, and protect against array out of bounds by the second condition.

After that you're passing NUMS

largest = maxnum(nums, SIZE);

whereas the array could contain fewer valid values. Just pass

largest = maxnum(nums, i);

edited Oct 15, 2016 at 7:43

answered Oct 15, 2016 at 7:37

Jean-François Fabre♦

141k24 gold badges179 silver badges246 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Jean-François Fabre Over a year ago

how true!! fixed. Thanks

Sumon Sarker · Accepted Answer · 2016-10-15 08:29:24Z

0

Here is another solution for your problem.

In main() function

int n,i=0;
  while(scanf("%d",&n) == 1){
    nums[i++] = n;
  }
n = maxnum(nums, i);
printf("The largest number is: %d\n", n);

Note : Initialize the value of i=0, Then input and update nums[] array

In maxnum() function

for(i = 0; i < maxx; i++)    {
  if(maxnumber < userarray[i]){
      maxnumber = userarray[i];
  }
}

Note: Start i=0 and find the max mumber and return the value

edited Oct 15, 2016 at 8:29

answered Oct 15, 2016 at 7:54

Sumon Sarker

2,7971 gold badge27 silver badges37 bronze badges

Collectives™ on Stack Overflow

While loop with user input validation to fill array, then search array for largest number.

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related