/*****************************************************************
 *  Find the sum of all the numbers from 20 to 2000, and         *
 *  print it.  This program uses a for loop to count through     *
 *  the numbers.  You also could have used a while loop to do    *
 *  it.  Notice that you don't need to read anything in for      *
 *  this program.                                                *
 *****************************************************************/
#include <stdio.h>

int
main(void)
{
    int count, sum = 0;

    for (count=20; count <=2000; count = count + 1)
        sum = sum + count;

    printf("The sum is %d\n", sum);

    return (0);
  }





/*****************************************************************
 *  Read in two numbers and tell whether their sum is greater   *
 *  than 500.  There are no loops in this program; just an       *
 *  if statement.                                                *
 *****************************************************************/
#include <stdio.h>

int
main(void)
{
    int number_1,number_2;

    printf("Enter a number: ");
    scanf("%d", &number_1);

    printf("Enter another number: ");
    scanf("%d", &number_2);

    if (number_1 + number_2 > 500)
        printf("The sum of %d and %d is greater then 500\n", 
                number_1,number_2);
    else
        printf("The sum of %d and %d is not greater than 500\n",
                number_1,number_2); 

    return (0);

  }





/*****************************************************************
 *  Read in floats until end of file.  Print out all numbers     *
 *  that are greater than 100 or less than 50.  I used a while   *
 *  loop to read through the numbers, as usual.  I use the OR    *
 *  operation to check the values.  The values need to be        *
 *  printed as soon as they are read in.                         *
 *****************************************************************/
#include <stdio.h>

int
main(void)
{
    float number;
    int input_status;

    input_status = scanf("%f",&number);

    while( input_status != EOF) {
        
        if (number > 100 || number < 50) 
            printf("%f is greater than 100 or less than 50\n", number);
        
        input_status = scanf("%f",&number);
      }        

    return (0);
  }





/*****************************************************************.
 *  Read in integers until end of file.  Count how many          *
 *  numbers are positive and how many numbers are negative.      *
 *  Print out the counts.  This program uses one variable to     *
 *  count positive numbers and another variable to count         *
 *  negative numbers.  If a 0 is entered, it is just ignored     *
 *  because it is not positive or negative.  The counters are    *
 *  incremented inside the loop, and the counts are printed out  *
 *  after the loop.                                              *
 *****************************************************************/
#include <stdio.h>

int
main(void)
{
    int number, count_positive = 0, count_negative = 0;
    int input_status;

    input_status = scanf("%d",&number);

    while( input_status != EOF) {

        if (number > 0)
             count_positive = count_positive + 1;
        else if (number < 0)
             count_negative = count_negative + 1;

        input_status = scanf("%d",&number);
      }

    printf("There were %d positive numbers\n", count_positive);
    printf("There were %d negative numbers\n", count_negative);

    return (0);
  }





/*****************************************************************.
 *  Read in numbers until you get two consecutive zeroes.        *
 *  than the first number you read in.  Print out the sum of the *
 *  numbers.  The while loop does not check for an end of        *
 *  file in this program; instead it checks for two consecutive  *
 *  zeroes.  The only printf statement is after the loop.        *
 *****************************************************************/
#include <stdio.h>
#define YES 1
#define NO 0

int
main(void)
{
    int number;            /* number you read in */
    int sum = 0;           /* sum of all numbers read in */
    int prev_zero;         /* Was last number a 0? */


    prev_zero = NO;
    scanf("%d", &number);

    while( number != 0 || prev_zero == NO )
      {
        sum = sum + number;
        if (number == 0) 
          prev_zero = YES;
        else 
          prev_zero = NO;
        scanf("%d", &number);
      }

    printf("The sum is %d\n", sum);

    return (0);
  }