C++ Exercises: Find the total number of minutes between two given times

Last update on August 11 2025 12:56:53 (UTC/GMT +8 hours)

Minutes Between Two Times

Write a C++ program to find the total number of minutes between two given times (formatted with a colon and am or pm).

Visual Presentation:

C++ Exercises: Find the total number of minutes between two given times

Sample Solution:

C++ Code :

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

// Function to calculate the difference in minutes between two times
int count_minutes(string time_str) {
    // Variables to store time components
    string num1, num2;
    string hr1, hr2, min1, min2;
    int index = time_str.find('-');
    bool colon = false;

    // Iterating through the time string to extract hour and minute values
    for (int x = 0; x < time_str.length(); x++) {
        if (x >= index) {
            colon = false;
            for (x; x < time_str.length(); x++) {
                if (time_str[x] == ':') {
                    colon = true;
                    continue;
                }

                if (time_str[x] == 'A' || time_str[x] == 'P') {
                    num2.push_back(time_str[x]);
                    num2.push_back(time_str[x + 1]);
                }

                if (colon && isdigit(time_str[x])) {
                    min2.push_back(time_str[x]);
                } else if (isdigit(time_str[x])) {
                    hr2.push_back(time_str[x]);
                }
            }
        } else {
            if (time_str[x] == ':') {
                colon = true;
                continue;
            }

            if (time_str[x] == 'A' || time_str[x] == 'P') {
                num1.push_back(time_str[x]);
                num1.push_back(time_str[x + 1]);
            }

            if (colon && isdigit(time_str[x])) {
                min1.push_back(time_str[x]);
            } else if (isdigit(time_str[x])) {
                hr1.push_back(time_str[x]);
            }
        }
    }

    // Calculating the hour difference
    int hr = 0;
    if (stoi(hr1) == stoi(hr2) && num1 == num2 && stoi(min1) > stoi(min2)) {
        hr = 24 - (stoi(hr1) - stoi(hr2));
    } else if (stoi(hr1) > stoi(hr2) && num1 == num2 && stoi(min1) < stoi(min2)) {
        hr = 24 - (stoi(hr1) - stoi(hr2));
    } else if (num1 == num2 || (hr2 == "12" && hr1 != "12")) {
        hr = stoi(hr2) - stoi(hr1);
    } else {
        hr = (12 - stoi(hr1)) + stoi(hr2);
    }

    // Calculating the total time difference in minutes
    int time;
    if (min1 != "00") {
        time = (hr * 60 - stoi(min1)) + stoi(min2);
    } else {
        time = (hr * 60 + stoi(min1)) + stoi(min2);
    }

    return time;
}

// Main function to test the count_minutes function with different time inputs
int main() {
    cout << "Minutes between 12:01AM to 12:00PM: "<< count_minutes("12:01PM-12:00PM") << endl;
    cout << "Minutes between 2:12AM to 2:8AM: "<< count_minutes("2:12AM-2:8AM") << endl;
    cout << "Minutes between 1:04PM to 1:29PM: "<< count_minutes("1:04PM-1:29PM") << endl;
    cout << "Minutes between 2:00PM to 10:00PM: "<< count_minutes("2:00PM-10:00PM") << endl;
    return 0;
}

Sample Output:

Minutes between 12:01AM to 12:00PM: 1439
Minutes between 2:12AM to 2:8AM: 1436
Minutes between 1:04PM to 1:29PM: 25
Minutes between 2:00PM to 10:00PM: 480

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to calculate the total minutes between two times given in 12-hour format with AM/PM.
Write a C++ program that converts two time strings into minutes since midnight and then computes the difference.
Write a C++ program to determine the number of minutes between two times by parsing the input string and handling edge cases at midnight.
Write a C++ program that reads two times with a colon separator and AM/PM markers, then calculates the total elapsed minutes accurately.

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