Why am I getting a function definition error in my C++ code?
Asked by
CoderGal123
I'm a beginner programmer trying to learn C++, and I'm stuck on a function definition error I'm encountering on HackerRank. Here's the code I wrote:
```cpp
int main() {
/* Enter your code here. Read input from STDIN. Print output to STDOUT */
int max_of_four(int a, int b, int c, int d) {
int max = 0;
if (max <= a) {
max == a;
}
if (max <= b) {
max == b;
}
if (max <= c) {
max == c;
}
if (max <= d) {
max == d;
}
return max;
}
return 0;
}
```
I'm receiving the following error message:
```
Solution.cpp: In function 'int main()':
Solution.cpp:11:48: error: a function-definition is not allowed here before '{' token
int max_of_four(int a, int b, int c, int d) {
^
```
I'm confused because I thought I was correctly defining my function. I did some research and it seems to relate to the braces, but I couldn't pinpoint the issue. Any insights would be greatly appreciated!
Answers
You really can't define a function inside another in C++. Move your `max_of_four` function outside of `main`, and it should compile. Also, just so you know, functions can be defined inside other functions using lambdas since C++11, but that's not what's happening here.
Reply to this answer
The error happens because in C++, you can't define a function inside another function. Your `max_of_four` function needs to be defined outside of `main`. The HackerRank template suggests putting the `max_of_four` function in the top-level, not inside `main`. Fixing that should solve your issue!
CoderGal123: That makes total sense! I didn't realize `main` is a function too, which is why I didn’t think about the placement. Thanks for the clarification!
Reply to this answer
Just a heads-up, don’t mix up `=` and `==`. One is used for assignment, and the other for checking equality. Once you sort out the function placement, this shouldn't be a problem for you anymore!
CoderGal123: Haha, I appreciate the reminder! That type of mistake often trips me up, so I’ll keep that in mind as I fix it!
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CoderGal123: Got it! I’ll make the changes. Lambdas sound fascinating—I'll definitely explore that when I'm more comfortable with the basics!