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2.8 Exercises

Given the following variables and their initializations:

int a, x, y, z;
     float b, u, v, w;

     x = 10; y= 20; z = 30;
     u = 4.0; v = 10.0;

1. (a)  a = x - y - z;
   (b)  a = x + y * z;
   (c)  a = z / y + y;
   (d)  a = x / y / z;
   (e)  a = x % y % z

2. (a)  a = (int) (u / v);
   (b)  a = (int) (v / u);
   (c)  b = v - u;
   (d)  b = v / u / w;

3. What are the results of the following mod operations:

   (a)   5  %  3
   (b)  -5  %  3
   (c)   5  % -3
   (d)  -5  % -3

4. (a)  (x <= y && x >= z)
   (b)  (x <= y || x >= z)
   (c)  (x <= y && !(x >= z))
   (d)  (x = y && z > y)
   (e)  (x == y && z > y)

5. Under what conditions are the following expressions True?

   (a)  (x = y && y = z)
   (b)  (x == y && y == z)
   (c)  (x == y || y == z)
   (d)  (x >= y && x <= z)
   (e)  (x > y && x < z)

6. Make required corrections in the following code.

   (a)
        main()
        {    int n;
   
             scanf("%d", n);
        }
   
   (b)
        main()
        {    float n;
   
             printf("%d", n);
        }
   
   (c)
   
        main()
        {    int n1, n2;
   
             if (n1 = n2)
                  printf("Equal\n");
             else
                  printf("Not equal\n");
        }

7. Find and correct errors in the following program that is supposed to read ten numbers and print them.

   main()
        {    int n, count;
   
             scanf("%d", &n);
             while (count < 10) {
                  printf("%d\n", n);
                  scanf("%d", &n);
             }
        }

8. We wish to print integers from 1 through 10. Check if the following loop will do so correctly.

   i = 1;
        while (i < 10) {
             printf("%d\n", i);
             i =  i + 1;
        }

9. Suppose a library fine for late books is: 10 cents for the first day, 15 cents per day thereafter. Assume that the number of late days is assigned to a variable late_days. Check if the following will compute the fine correctly.

   if (late_days == 1)
             fine = 0.10;
        else
             fine = late_days * 0.15;