Division of integers that produces an integer quotient. How the fractional part is handled differs between languages: some truncate toward zero (C, Java), and others round down toward negative infinity (Python's //). The results are the same for positive numbers but differ for negative ones.
Japanese name: 整数除算
Integer division appears in 4 practice questions across 3 topics, including Computer Arithmetic, Programming Basics (Pseudocode Tracing), C Programming Basics.
Dividing −7 by 2 gives a quotient of −3 and a remainder of −1 in C and Java, which truncate toward zero. Python's //, which rounds down, gives a quotient of −4, and % gives a remainder of 1. In both, "quotient × divisor + remainder = dividend" holds; the remainder takes the sign of the dividend in C and the sign of the divisor in Python. This causes mistakes when programs that handle negative numbers are rewritten in another language.
Pseudocode questions explain in the question how the fractional part of ÷ is handled. For example, if the question says "the fractional part is discarded when assigning to an integer variable", assigning (lo + hi) ÷ 2 to the integer variable mid drops the 0.5 when lo + hi is odd. This truncation affects results such as the middle position in a binary search.
Integer division by a power of 2 can also be computed with a right shift in binary. For unsigned integers, x divided by 2 is x shifted right by 1 bit. However, an arithmetic right shift of a negative number rounds down, so the result can differ from truncation toward zero.
Answer: C. Positive infinity
IEEE 754 specifies that dividing a nonzero number by zero returns positive or negative infinity according to the signs. Infinity is encoded with an all-ones exponent and a zero significand and is also the result of overflow. Computation can continue without stopping, and anomalies can be found by inspecting results later. 0 ÷ 0, which has no defined value, gives NaN. Unlike integer division, floating point does not trap by default.
Answer: A. −7 / 2 is −3, and −7 >> 1 is −4
C (since C99) defines integer division as truncating toward zero, so −3.5 becomes −3. An arithmetic right shift instead rounds toward negative infinity: shifting −7 (1111 1001) right by one gives 1111 1100 = −4. For negative numbers, shifting and dividing therefore disagree, so when compilers replace division by 2 with a shift they add correction instructions for negatives. For positive numbers the two agree.
Integer division by zero is a runtime error (an exception) in many languages and undefined behavior in C. Programs should check that the divisor is not zero before dividing.
With quotient q and remainder r, dividend = q × divisor + r. The quotient and remainder are defined as a pair, so if the rounding of the quotient changes (truncation or rounding down), the remainder changes too.
Unlike integer division, floating point does not trap by default.
Under IEEE 754, what result does the standard specify for d…C (since C99) defines integer division as truncating toward zero, so −3.5 becomes −3.
In C, what are the results of −7 / 2 and −7 >> 1 (with an a…x mod 10 takes the ones digit of x, and x ← x ÷ 10, which becomes integer division because the fractional part is discarded, removes it.
÷ is division; when the result is assigned to an integer va…a / b divides an int by an int, so it is integer division and gives 3, with the fractional part discarded.
Which of the following is the output when the code above, w…As an Amazon Associate I earn from qualifying purchases.
Variable IEEE 754 Significand NaN Arithmetic shift Argument Modulo operation Array Bitwise operation Control structure