# Set a variable without using Arithmetic, Relational or Conditional Operator

Given three integers a, b and c where c can be either 0 or 1. Without using any arithmetic, relational and conditional operators set the value of a variable x based on below rules –

If c = 0x= a Else // Note c is binaryx= b.

Examples:

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Input:a = 5, b = 10, c = 0;Output:x = 5Input:a = 5, b = 10, c = 1;Output:x = 10

**Solution 1:** Using arithmetic operators

If we are allowed to use arithmetic operators, we can easily calculate x by using any one of below expressions –

x = ((1 - c) * a) + (c * b) OR x = (a + b) - (!c * b) - (c * a); OR x = (a * !c) | (b * c);

`#include <iostream>` `using` `namespace` `std;` ` ` `int` `calculate(` `int` `a, ` `int` `b, ` `int` `c)` `{` ` ` `return` `((1 - c) * a) + (c * b); ` `}` ` ` `int` `main()` `{` ` ` `int` `a = 5, b = 10, c = 0;` ` ` ` ` `int` `x = calculate(a, b, c);` ` ` `cout << x << endl;` ` ` ` ` `return` `0;` `}` |

Output:

5

**Solution 2: **Without using arithmetic operators

The idea is to construct an array of size 2 such that index 0 of the array stores value of variable ‘a’ and index 1 value of variable b. Now we return value at index 0 or at index 1 of the array based on value of variable c.

`#include <iostream>` `using` `namespace` `std;` ` ` `int` `calculate(` `int` `a, ` `int` `b, ` `int` `c)` `{` ` ` `int` `arr[] = {a, b};` ` ` `return` `*(arr + c);` `}` ` ` `int` `main()` `{` ` ` `int` `a = 5, b = 10, c = 1;` ` ` ` ` `int` `x = calculate(a, b, c);` ` ` `cout << x << endl;` ` ` ` ` `return` `0;` `}` |

Output:

10

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