Classic and Basic C/C++ Question
There are four classical question abount C/C++ interview.
Question 1: Fibonacci Sequence
Version 1
This is a recursive function method.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
| #include <iostream>
using namespace std;
int fib(int n){
if(n == 0) return 0;
if(n == 1) return 1;
return fib(n -1) + fib(n-2);
}
int main() {
int n;
cout << "Please give n:"
cin >>n;
for(int i = 0; i < 7; ++i){
cout << fib(i) << " ";
}
return 0;
}
|
Version 2
This is an iteration method.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
| #include <iostream>
using namespace std;
void fib(int n){
int curr = 0;
int next1 = 1;
int next2 = 0;
for(int i = 0; i < n; ++i){
cout << curr << " ";
next2 = curr + next1;
curr = next1;
next1 = next2;
}
}
int main() {
int n;
cout << "Please give n:";
cin >>n;
fib(n);
return 0;
}
|
Question 2: Palindrome Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
| #include <iostream>
using namespace std;
bool palindrome(int n){
if(n < 0 || (n!=0 && n %10 == 0)) return false;
int res = 0;
while(n > res){
res = res*10 + n % 10;
n /= 10;
}
return (res == n) || (res / 10 == n);
}
int main() {
int n;
cout << "Please give n:";
cin >>n;
cout << boolalpha;
cout << palindrome(n);
return 0;
}
|
Question 3: Check number if it's prime number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
| #include <iostream>
#include <vector>
using namespace std;
bool primeNumber(int n){
if(n < 2) return false;
vector<int> v(n + 1, 0);
int vNumber = v.size();
int i = 2;
while(i < vNumber){
if(v[i] == 0){
for(int j = 2; i*j < vNumber; ++j){
v[i*j] = 1;
}
}
++i;
}
return (v[n]==0)?true:false;
}
int main() {
int n;
cout << "Please give n:";
cin >>n;
cout << boolalpha;
cout << primeNumber(n);
return 0;
}
|
Question 4: Draw Pyramid and Triangle
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
| #include <iostream>
#include <vector>
using namespace std;
void drawPyramid(int floors){
for(int i = 1; i <= floors; ++i){
for(int j = 1; j <= floors - i; ++j){
cout << " ";
}
for(int k = 1; k <= i*2 - 1; ++k){
cout << "*";
}
cout << endl;
}
cout << endl;
}
void drawInvertedPyramid(int floors){
for(int i = floors; i >= 1; --i){
for(int j = i; j < floors; ++j ){
cout << " ";
}
for(int k = 1; k <= i*2 - 1; ++k){
cout << "*";
}
cout << endl;
}
cout << endl;
}
void drawTriangle(int floors){
for(int i = 1; i <= floors; ++i){
for(int j = 1; j <= i*2 - 1; ++j){
cout << "*";
}
cout << endl;
}
cout << endl;
}
void drawInvertedTriangle(int floors){
for(int i = floors; i >= 1; --i){
for(int j = i; j >= 1; --j){
cout << "*";
}
cout << endl;
}
cout << endl;
}
int main() {
int f;
cout << "Please give f:";
cin >> f;
drawPyramid(f);
drawInvertedPyramid(f);
drawTriangle(f);
drawInvertedTriangle(f);
return 0;
}
|