This section on advanced C++ programming questions on “Floating Point Types”. One shall practice these advanced C++ questions to improve their C++ programming skills needed for various interviews (campus interviews, walk-in interviews, company interviews), placements, entrance exams and other competitive exams. These questions can be attempted by anyone focusing on learning C++ programming language. They can be a beginner, fresher, engineering graduate or an experienced IT professional. Our advanced C++ questions come with the detailed explanation of the answers which helps in better understanding of C++ concepts.
Here is a listing of advanced C++ programming questions on “Floating Point Types” along with answers, explanations and/or solutions:
1. Which of the following is not one of the sizes of the floating point types?
a) short float
b) float
c) long double
d) double
Answer: a
Clarification: Floating point types occur in only three sizes-float, long double and double.
2. Which of the following is a valid floating-point literal?
a) f287.333
b) F287.333
c) 287.e2
d) 287.3.e2
Answer: c
Clarification: To make a floating point literal, we should attach a suffix of ‘f’ or ‘F’ and there should not be any blank space.
3. What is the range of the floating point numbers?
a) -3.4E+38 to +3.4E+38
b) -3.4E+38 to +3.4E+34
c) -3.4E+38 to +3.4E+36
d) -3.4E+38 to +3.4E+32
Answer: a
Clarification: This is the defined range of floating type number sin C++. Also range for +ve and -ve side should be same so the answer is -3.4E+38 to +3.4E+38.
4. Which of three sizes of floating point types should be used when extended precision is required?
a) float
b) double
c) long double
d) extended float
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Answer: c
Clarification: Float for single precision, double for double precision and long double for extended precision.
5. What will be the output of the following C++ code?
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#include
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using namespace std;
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int main()
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{
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float num1 = 1.1;
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double num2 = 1.1;
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if (num1 == num2)
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cout << "stanford";
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else
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cout << "harvard";
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return 0;
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}
a) harvard
b) stanford
c) compile time error
d) runtime error
Answer: a
Clarification: Float store floating point numbers with 8 place accuracy and requires 4 bytes of Memory. Double has 16 place accuracy having the size of 8 bytes.
Output:
$ g++ float3.cpp
$ a.out
harvard
6. What will be the output of the following C++ code?
-
#include
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#include
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using namespace std;
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int main()
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{
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cout << setprecision(17);
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double d = 0.1;
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cout << d << endl;
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return 0;
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}
a) 0.11
b) 0.10000000000000001
c) 0.100001
d) compile time error
Answer: b
Clarification: The double had to truncate the approximation due to its limited memory, which resulted in a number that is not exactly 0.1.
Output:
$ g++ float2.out
$ a.out
0.10000000000000001
7. What will be the output of the following C++ code?
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#include
-
using namespace std;
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int main()
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{
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float i = 123.0f;
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cout << i << endl;
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return 0;
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}
a) 123.00
b) 1.23
c) 123
d) compile time error
Answer: c
Clarification: The value 123 is printed because of its precision.
$ g++ float.cpp
$ a.out
123
8. Which is used to indicate single precision value?
a) F or f
b) L or l
c) Either F or for L or l
d) Neither F or for L or l
Answer: a
Clarification: Either F or f can be used to indicate single precision values.
9. What will be the output of the following C++ code?
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#include
-
using namespace std;
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int main()
-
{
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float f1 = 0.5;
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double f2 = 0.5;
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if (f1 == 0.5f)
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cout << "equal";
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else
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cout << "not equal";
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return 0;
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}
a) equal
b) not equal
c) compile time error
d) runtime error
Answer: a
Clarification: 0.5f results in 0.5 to be stored in floating point representations.
Output:
$ g++ float.cpp
$ a.out
equal
10. Which is correct with respect to the size of the data types?
a) char > int < float
b) int < char > float
c) char < int < float
d) char < int < double
Answer: d
Clarification: The char has less bytes than int and int has less bytes than double whereas int and float can potentially have same sizes.
