C++ Exercises: Reads a sequence of integers and prints mode values of the sequence

Last update on August 11 2025 12:58:03 (UTC/GMT +8 hours)

Find Mode in Sequence

Write a C++ program that reads a sequence of integers and prints the mode values of the sequence. The number of integers is greater than or equal to 1 and less than or equal to 100.
Note: The mode of a set of data values is the value that appears most often.

Sample Solution:

C++ Code :

#include <iostream> // Including input-output stream header file
#include <vector> // Including vector header file
using namespace std; // Using the standard namespace

int main() {
    vector<int> nums(101, 0); // Declaring a vector 'nums' of size 101 initialized with zeros
    int n, mode = 0; // Declaring variables 'n' for input number and 'mode' to store the mode value

    while (cin >> n) { // Continuously reads integers until the input stream fails
        nums[n]++; // Incrementing the count of the corresponding index in the 'nums' vector for the input number 'n'
        if (nums[n] > mode) { // Checking if the count of the current number is greater than the mode
            mode = nums[n]; // If so, update the mode value
        }
    }

    // Loop through the 'nums' vector to find and print the mode(s)
    for (int i = 0; i != nums.size(); ++i) {
        if (nums[i] == mode) { // Checking if the count at index 'i' is equal to the mode
            cout << i << endl; // If true, print the index (which represents the mode(s))
        }
    }

    return 0; // Indicating successful completion of the program
}

Sample Output:

0
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
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C++ program to determine the mode of a sequence of integers using a hash map and then display all modes in case of ties.
• Write a C++ program that reads a sequence of numbers, computes the frequency of each, and outputs the mode along with its frequency.
• Write a C++ program to find the mode in a sequence of integers without using any STL containers by sorting the array first.
• Write a C++ program that calculates the mode of a sequence, then verifies if the mode occurs more than half the time.

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