Why does compiler say invalid operands to binary & (have char* and int)

(I honestly can't see anything wrong here.

Code:

---

#include <stdio.h>

int main()


{
        int num1; /*Variable to hold num*/
        printf:("Please enter a number:\n");
        scanf:("%d" &num1);
               
if (num1%2==0) /*If clause to determine if number is prime*/
{
printf("Number %d is a prime number.\n" ,num1);
}


else
{
printf("Number %d is not a prime number.\n" ,num1);
}


return 0; /*Exits the program*/
}

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You are missing a comma in your scanf() between the format string and the variable.

In the future when you have a compile, linker error post the complete error message exactly as it appears in your development environment. These messages have information to help pinpoint the location of the error.

Jim

Edit: jimblumberg has the correct answer; but, I still wonder.

Code:

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scanf:("%d" &num1);

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Why is there a ":" after scanf and printf?

Tim S.

Take the colons out of lines 8 and 9 ... it's printf( not printf:

Also num % 2 does not indicate if a number is prime or not... it indicates whether it's even or odd.

Prime numbers are numbers that can only be divided evenly by 1 and themselves.

eg.
... 3 is prime ... 3/2 = 1.5
... 4 is not ... 4/2 = 2

Oddly, it now compiles, but assigns its own number to the num1 variable and tells me 2147315712 is a prime number.

I want it to prompt for a number and scanf it. I have a printf statement so can't figure out why it doesn't print that.

Show your current code.

Jim

Thanks all! Colons after printf/scanf. Crazy the mistakes that are made when I'm stressed.

Quote:

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Originally Posted by Interista

Oddly, it now compiles, but assigns its own number to the num1 variable and tells me 2147315712 is a prime number.

I want it to prompt for a number and scanf it. I have a printf statement so can't figure out why it doesn't print that.

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Sounds like scanf() isn't working...