错误：“ <=”令牌之前的预期主表达式

Question

Below is a simple program that prompts user to enter number. The user is assigned a fail, pass, merit or distinction grade based on the value entered:

#include <iostream>

using namespace std;

// 0-30 Fail
// 31-40 Pass
// 41-50 Merit
// 51 and over Distinction

int main()
{
    int yourScore;

    cout << "Please enter your score: " << endl;
    cin  >> yourScore;

    if (yourScore <=30)
    {
        cout << "Your grade is fail. Better luck next time." << endl;
    }
    else if (yourScore >30 && <=40)
    {
        cout << "Your grade is pass. Good." << endl;
    }
    else if (yourScore >41 && <=50)
    {
        cout << "Your grade is merit. Well done." << endl;
    }
    else
    {
        cout << "Your grade is distinction. Excellent." << endl;
    }
    return 0;
}

Attempting to compile the above code produces following errors:

main.cpp|21|error: expected primary-expression before '<=' token main.cpp|25|error: expected primary-expression before '<=' token

I've tried adding parentheses around >30 && <=40 and >41 && <=50 , which produced more errors.

Where am I going wrong?

Answer 1

should be

yourScore>30 && yourScore<=40

imagine that each condition accounts for a true or false value. in your code (<=40) is not an actual boolean expression. you have to have to operands