#include <iostream>
#include <iomanip>
using namespace std; //using standard name space


//list of functions to be used for determining the time that is printed onto the screen
int getTime24(int& hour, int& min, char& colon);
void convertTime24to12(int hour, int anHour);
void printTime24(int hour, int min);
void printTime12(int hour, int min);
int userWantsToContinue(string userInput, int anHour);
int main()
{
    //list of local variables used to store information and pass it into the functions
    int min, hour;
    int anHour;
    char colon;
    string userInput;

    //list of functions called into the main body of the script
    getTime24(min, hour, colon);
    convertTime24to12(hour, anHour);
    printTime12(hour, min);
    printTime24(hour, min);
    cout << "do you want to continue? ";
        cin >> userInput;
    userWantsToContinue(userInput,anHour);
}

//function to ask the user for the time in a 24 hour format and decide if it is acceptable.
int getTime24(int& hour, int& min, char& colon) {
    cout << "Enter a time in 24 hour format (for example 13:45):";
    cin >> hour >> colon >> min;
    while (!((hour >= 0 && hour <= 24) && (min >= 00 && min <= 59))) {
        cout << "That is the wrong format. Please try again (for example 13:45): ";
        cin >> hour >> colon >> min;
    }
    return(hour, min, colon);
}

//function to convert the time to a 12 hour time and store it in a variable
void convertTime24to12(int hour, int anHour) {
    if (hour >= 12 && hour <= 24) {
        anHour = hour - 12;
    }
    else
        anHour = hour;
}

//function to print the time in a 24 hour format
void printTime24(int hour, int min) {
    cout << "That time in 24 hour format is: " << hour << ":" << min << "\n";
}
//function to print the time in a 12 hour format
void printTime12(int hour, int min) {
    if (hour >= 12 && hour <= 24) {
        cout << "That time in 12 hour format is: " << hour - 12 << ":" << min << "\n";
    }
}
//asks the user if they want to continue and ends the script if they type anything but yes
int userWantsToContinue(string userInput,int anHour) {
    cout << "do you want to continue?";
    cin >> userInput;
    while (userInput == "yes") {
        int hour, min;
        int anHour;
        char colon;
        getTime24(min, hour, colon);
        convertTime24to12(hour, anHour);
        printTime12(hour, min);
        printTime24(hour, min);
        userWantsToContinue(userInput,anHour);
    }
    return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

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

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}