Ошибка expected primary expression before int

The expected primary expression before occurs due to syntax errors. It usually has a character or a keyword at the end that clarifies the cause. Here you’ll get access to the most common syntax mistakes that throw the same error.

Continue reading to see where you might be getting wrong and how you can solve the issue.

Why Does the Expected Primary Expression Before Occur?

The expected primary expression before error occurs when your code doesn’t follow the correct syntax. The mistakes pointed out below are the ones that often take place when you are new to programming. However, a programmer in hurry might make the same mistakes.

So, here you go:

– You Are Specifying the Data Type With Function Argument

If your function call contains the data type along with the argument, then you’ll get an error.

Here is the problematic function call:

int addFunction(int num1, int num2)
{
int sum;
sum = num1 + num2;
return sum;
}
int main()
{
int result = addFunction(int 20, int 30);
}

– The Wrong Type of Arguments

Passing the wrong types of arguments can result in the same error. You can not pass a string to a function that accepts an argument of int data type.

int main()
{
int result = addFunction(string “cat”, string “kitten”);
}

– Issue With the Curly Braces Resulting in Expected Primary Expression Before }

Missing a curly bracket or adding an extra curly bracket usually results in the mentioned error.

– The Parenthesis Following the If Statement Don’t Contain an Expression

If the parenthesis in front of the if statement doesn’t contain an expression or the result of an expression, then the code won’t run properly. Consequently, you’ll get the stated error.

How To Fix the Given Error?

You can fix the “expected primary-expression before” error by using the solutions given below:

– Remove the Data Type That Precedes the Function Argument

Remove the data type from the parenthesis while calling a function to solve the error. Here is the correct way to call a function:

int main()
{
int result = addFunction(30, 90);
}

– Pass the Arguments of the Expected Data Type

Double-check the function definition and pass the arguments of the type that matches the data type of the parameters. It will ensure that you pass the correct arguments and kick away the error.

– Ensure The Equal Number of Opening and Closing Curly Brackets

Your program must contain an equal number of opening and closing curly brackets. Begin with carefully observing your code to see where you are doing the mistake.

– Add an Expression in the If Statement Parenthesis

The data inside the parenthesis following the if statement should be either an expression or the result of an expression. Even adding either true or false will solve the issue and eliminate the error.

FAQ

You can view latest topics and suggested topics that’ll help you as a new programmer.

– What Does It Mean When the Error Says “Expected Primary Expression Before Int” in C?

The “expected primary expression before int” error means that you are trying to declare a variable of int data type in the wrong location. It mostly happens when you forget to terminate the previous statement and proceed with declaring another variable.

– What Is a Primary Expression in C Language?

A primary expression is the basic element of a complex expression. The identifiers, literals, constants, names, etc are considered primary expressions in the C programming language.

– What Are the Types of Expressions?

The different types of expressions include arithmetic, character, and logical or relational expressions. An arithmetic expression returns an arithmetic value. A character expression gives back a character value. Similarly, a logical value will be the output of a logical or relational expression.

Conclusion

The above error revolves around syntax mistakes and can be solved easily with a little code investigation. The noteworthy points depicting the solutions have been written below to help you out in removing the error:

• Never mention the data type of parameters while calling a function
• Ensure that you pass the correct type of arguments to the given function
• You should not miss a curly bracket or add an extra one
• The if statement should always be used with the expressions, expression results, true, or false

The more you learn the syntax and practice coding, the more easily you’ll be able to solve the error.

Your problem is that your are using asterisks («*»)

   for(int j=0;j>-1;j++) {
     **j= Serial.read(int p1, int p2, int p3);**
   }

The asterisk in C/C++ is the pointer operator. You use to get the value pointed by a pointer.

The expression **j means that j is a pointer to a pointer that points something. That’s is meaningless here.

Then, the last ** is readed as another pointer to a pointer, and the compiler is expecting a variable or expression that give the value for the pointer, but found «}», which is an error.

You probably tried to comment out that line of code after the compiler barks at the Serial.read(), which, as Dave X pointed out, is illegal, because Serial.read() takes no arguments.

And, the syntax function(int x) is only use for declaring a function, not for calling one.