C/C++ expected primary-expression before "else"

Question

can someone help me? im just starting programming on C/C++ (im using DevC++)

#include <iostream>
#include <cstdlib>

using namespace std;

int main(int argc, char* argv[]) {
    int X;
    int Y;
    int R;
    cout << "FUNCION POTENCIA";
    cout << "Ingrese primero la base y luego el exponente";
    cin >> X, Y;
    if (Y = 1) {
        R = X;
    };
    //if
    else() {
        do
            while (Y > 0) {
                R = X * X;
                Y--;
            }; //do while
    }; //else   cout<< R;
    system("PAUSE");
    return EXIT_SUCCESS;
} //main

`else()` is wrong, it should be `else`. Please read a few tutorials about the subject before asking questions here. And welcome to Stack Overflow! — holgac, Apr 13 '15 at 20:38
remove ; before else, also there should not be any parenthesis with else (else() is wrong) — cosmos, Apr 13 '15 at 20:38
Unforutunately you have syntax errors all over the place. If you fix that one you will just get the next one. Probably better if you go back and read a beginner's tutorial. Using stackoverflow as a line by line syntax checker isn't going to work well :-) — kaylum, Apr 13 '15 at 20:39
C/C++ isn't a language. Judging by your code it seems you're learning C++. — Emil Laine, Apr 13 '15 at 20:50

score 2 · Answer 1 · edited May 23 '17 at 11:57

You have five errors:

cin >> X, Y; doesn't read user input to both X and Y. It's actually two separate statements: cin >> X; and Y;. The first one reads user input to X, the second one evaluates the current value of Y and doesn't do anything to it. To read user input to both variables: cin >> X >> Y;.
if (Y = 1) will assign 1 to Y. You want to check for equality with ==: if (Y == 1) i.e. "if Y is equal to 1".
Don't put semicolons after if, else, and while blocks. They're redundant and cause errors like this. Put semicolons only after statements.
Don't put () after else.
A do-while loop is do { ... } while (...); not do while (...) { ... }, whereas a while loop is simply while (...) { ... }.

Here's the correct version:

...
cin >> X >> Y; // 1.

if (Y == 1) { // 2.
    R = X;
} // 3.
else { // 4.
    while (Y > 0) { // 5.
        R = X * X;
        Y--;
    }

    // or if you want a do-while:
    do {
        R = X * X;
        Y--;
    } while (Y > 0); // semicolon here!
}

In conclusion, pick a book to learn the language properly, so you can stop guessing what the right syntax is.

score 0 · Answer 2 · answered Apr 13 '15 at 20:38

0

It's because you have a semicolon after your if statement. Correct if statement form is:

if(expression)
{
     // If Code
}
else
{
     // Else code
}

answered Apr 13 '15 at 20:38

Bob

1,779
3
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35

Remove the () after the else, and the pretty much any semicolon that immediately follows a close bracket. I could be forgetting something but I don't think }; is ever correct syntax. – Bob Apr 13 '15 at 20:43

score 0 · Answer 3 · answered Apr 13 '15 at 20:38

0

 if (Y = 1) {
        R = X;
 };

Remove the last ";" here.

answered Apr 13 '15 at 20:38

victor175

624
3
10
23

C/C++ expected primary-expression before "else"

3 Answers3