CODEWITHSUNDEEP
c
Arcanium
Arcanium

Reputation: 37

newbie in c and issue with integers

#include <stdio.h>

int main(int argc, const char * argv[])
{
  int x =10, y =20, b = 500;
  int z = x*y;
  int f = z/b;

  // insert code here...
  printf("x is:%d, y is:%d, b is %d\n",x,y,b);
  printf("x times y is: %d\n",z);
  printf("z divided by b is: %d\n",f);
  return 0;
}

on print out f = 0. Why?

Upvotes: 2

Views: 166

Answers (4)

C.Champagne
C.Champagne

Reputation: 5489

I am not "fluent" in C but I think you should use float instead of int. A division of an integer by an integer will return an integer.

Note also that you should use %f instead of %d to display float in prinf

Your code should be :

//
//  main.c
//  cmd4
//
//  Created by Kevin Rudd on 27/06/13.
//  Copyright (c) 2013 Charlie Brown. All rights reserved.
//

#include <stdio.h>

int main(int argc, const char * argv[])
{
  float x =10.0, y =20.0, b = 500.0;
  float z = x*y;
  float f = z/b;

  // insert code here...
  printf("x is:%f, y is:%f, b is %f\n",x,y,b);
  printf("x times y is: %f\n",z);
  printf("z divided by b is: %f\n",f);
  return 0;
}

Upvotes: 2

paul
paul

Reputation: 1705

The int type is an integer, which holds values that you can use to count (1, 2, 3...). It does not handle anything past a decimal point.

If I were to assign a value with anything past the decimal to an int, all the numbers on the right-hand side of the decimal would be truncated:

int v = 3.14159

would leave me with a value of 3 for v, because the integer can't store the .14159.

Your value of 200/500 is 0.4, which is truncated to 0 when it is assigned to the int f.

In order to store decimal values, you have to use a float or double type. Do note that these types are not as precise as you might think, so if you assign a value of 4.57 you might end up with an actual value of something like 4.569999999....

In your code, you'd want to change the type of f to a float, and you'd probably want to do a cast from integer to float on the items you're dividing to make sure they keep any floating point information.

So, your line of

int f = z/b;

would become

float f = (float)z/(float)b;

and then you'd use the %.1f in your printf as @BalogPal suggested.

Upvotes: 5

Balog Pal
Balog Pal

Reputation: 17163

Integer division is defined that way. It just drops the remainder for 300/500 and leaves you with 0.

Upvotes: 0

1737973
1737973

Reputation: 118

Because the integer division of a and b is 0 when a is less than b you know. You see C behaves differently from Python!

Upvotes: -1

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