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Muhammad Magdi

Remember

  • We must declare a variable and give it a name before using it.
  • cin is used to get input from user into a variable.
  • cout is used to print something on the screen.
  • every variable in C++ has a Data Type.
  • Data types in C++ are:
Data Type Description
int Small integer number
double Large real number
long long Large integer number
string A sequence of characters (word)
char A single character
bool Boolean number (0 or 1)
 

Remember

Sometimes we need to execute statements depending on particular conditions, so we use if conditions:

if ( CONDITION#1 ) {

    TRUE-STATEMENTS#1

} else if ( CONDITION#2 ) {
    TRUE-STATEMENTS#2
} else if ( CONDITION#3 ) {
    TRUE-STATEMENTS#3
} ... and so on
... else {
    FALSE-STATEMENTS
}

Remember

Arithmetic (in Calculations) Operators in C++ are:

Operator Meaning
+ Addition
- Subtraction
* Multiplication
/ Integer Division
% Remainder after Division (Mod)

Relational (in Conditions) Operators in C++ are:

Operator Meaning
== equal to
!=
 not equal to
< less than
> greater than
<= less than or equal
>= greater that or equal

Logical (in Conditions) Operators in C++ are:

Operator Meaning
&& AND
|| OR
! NOT

Calculator Program

#include <iostream>

using namespace std;

int main(){
    int a, b;
    char op;
    cin >> a >> op >> b;
    if (op == '+') {
        cout << a + b << endl;
    } else if (op == '-') {
        cout << a - b << endl;
    } else if (op == '*') {
        cout << a * b << endl;
    } else if (op == '/') {
        cout << a / b << endl;
    }
    return 0;
}

URI 1046 - Game Time

URI 1046 - Game Time

[Problem Summary]

  • There is game that started at time start and ended at time end
  • Write a program that takes start and end .
  • Calculate and Print the Duration of the game in the form:
    "O JOGO DUROU Duration HORA(S)"
  • Follow this message with an endl

URI 1046 - Game Time

[Solution]

#include <iostream>

using namespace std;

int main(){
    int start, end;
    cin >> start >> end;
    if (start < end) {
        cout << "O JOGO DUROU " << end - start << " HORA(S)" << endl;
    } else {
        cout << "O JOGO DUROU " << 24 - start + end << " HORA(S)" << endl;
    }
    return 0;
}

URI 1046 - Game Time

[Discussion]

There are two cases:

Case 1:

When the game starts and ends within the same day.

In this case start will be less than end.

So the Duration will be the difference end - start.

Case 2:

When the game starts in a day and ends in the following one.

In this case start will be greater than end, as it started late (with large value) in day1 and ended early (with small value) in day2.

So the Duration here is consisted of 2 parts:

Day1 Part = 24 - start

Day2 Part = end

Duration = 24 - start + end

Thanks

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By Muhammad Magdi

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