Exercise 3-14 (The ternary operator, IfThen)

Chapter_3     Exercise_3-13

Comma     Exercise_3-15

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Exercise 3-14     TCP1, p. 228

Exercise 3-14. Modify Ifthen.cpp (Section ch3-Controlling_Execution) to use the ternary if-else operator (?:).

Ternary.cpp         download

// Demonstration of ternary operator
#include <iostream>
using std::cout;
using std::cin;
using std::endl;

int main()
{
int i;

cout << "Type a number and 'Enter'" << endl;
cin >> i;

(i > 5) ? cout << "It's greater than 5" << endl
: // i <= 5
(i < 5) ? cout << "It's less than 5" << endl
: cout << "It's equal to 5" << endl;
// More formal:
(i > 5) ? cout << "It's greater than 5" << endl
: // i <= 5
(
(i < 5) ? cout << "It's less than 5" << endl
: cout << "It's equal to 5" << endl
);

cout << "Type a number and 'Enter'" << endl;
cin >> i;

(i < 10) ?
(
(i > 5) ? cout << "5 < " << i << " < 10" << endl
: cout << i << " <= 5" << endl
)
: cout << i << " >= 10" << endl;

return 0;
}
/*
g++ Ternary.cpp -o Ternary
./Ternary
Type a number and 'Enter'
1
It's less than 5
It's less than 5
Type a number and 'Enter'
2
2 <= 5

./Ternary
Type a number and 'Enter'
5
It's equal to 5
It's equal to 5
Type a number and 'Enter'
6
5 < 6 < 10

./Ternary
Type a number and 'Enter'
7
It's greater than 5
It's greater than 5
Type a number and 'Enter'
10
10 >= 10
*/

Note:  See also ch2-items and Exercise_2-10 on the blog Kernighan_and_Ritchie, Chapter_2, Sec. 2.11.

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