i have a task in c . I have to write program checks whether a number is between 10 and 50. I wrote something but it errors, can you help me please.

#include <iostream>
using namespace std;

int main()
{
    int a;
    
    cout << "enter number";
    cin >> a;
    
    if ( 10 < a < 50)
        cout << "True";
    else
        cout << "False";


   return 0;
}

CodePudding user response：

The expression 10 < a < 50 is actually the same as (10 < a) < 50.

So it compares the boolean true or false result of 10 < a with the integer value 50.

The comparison will always be true, since 10 < a will be either 0 or 1 when converted from false or true, respectively.

You need to make two separate comparisons, chained together with the logic AND operator &&, like 10 < a && a < 50.

CodePudding user response：

You can't write if statements like a < b < c. You can compare only two things at the moment, so, you have to change your if statement like that

if (a > 10 && a < 50){
    // correct
} else {
    // not correct
}

In C , && is a logic AND, while || is a logic OR. Now, this statement means "if a is more than 10 AND a is fewer than 50.

Update

Actually, you can compare a < b < c, but this will lead to behavior that you probably are not expecting. Instead of that, will be better to use logic AND and logic OR to separate such a comparements into several, much simple comparements like a < b AND b < c.