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February 3rd, 2017, 04:27 AM
#1
I need help with pointers (& and *) and functions
I'm trying to return the pointer to the variable that has the bigger value using pointers & and *. Below is the source code for my main.cc, functions.cc, and functions.h files. What did I do wrong here? I have also posted the error that it gave me.
ERROR STATEMENT:
functions.cc:9:10: error: cannot initialize return object of type 'int *' with
an lvalue of type 'int'
return *a;
^~
functions.cc:11:10: error: cannot initialize return object of type 'int *' with
an lvalue of type 'int'
return *b;
^~
2 errors generated.
make: *** [functions.o] Error 1
main.cc
Code:
#include <string>
#include <cstdio>
#include <vector>
#include "functions.h"
using namespace std;
int main( int argc, char** argv ) {
int x = 100;
int y = 200;
int result = 0;
// find out which of the two variables (x and y) is the largest
pointerToMax(&x, &y);
}
functions.cc
Code:
#include <string>
#include <cstdio>
#include <vector>
#include "functions.h"
using namespace std;
int* pointerToMax(int* a, int* b) {
if(a > b) {
return *a;
} else {
return *b;
}
} // end of pointerToMax
functions.h
Code:
#ifndef FUNCTIONS_H
#define FUNCTIONS_H
int* pointerToMax(int* a, int* b);
#endif
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February 3rd, 2017, 04:42 AM
#2
Re: I need help with pointers (& and *) and functions
This has been answered elsewhere.
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February 3rd, 2017, 05:01 AM
#3
Re: I need help with pointers (& and *) and functions
A couple of further points
Code:
int main( int argc, char** argv ) {
unless argc and argv are used within the code, this is usually written as
Also
Code:
if(a > b) {
return *a;
} else {
return *b;
}
as there is only one statement within each branch of the condition, the brackets are not needed and could be written as
Code:
if (a > b)
return *a;
else
return *b;
or using the tertiary operator as
Code:
return (a > b) ? *a : *b;
(which still requires the error fix as mentioned in the other place).
Looking at
Code:
pointerToMax(&x, &y);
This calls the function but does nothing with the returned value!
All advice is offered in good faith only. All my code is tested (unless stated explicitly otherwise) with the latest version of Microsoft Visual Studio (using the supported features of the latest standard) and is offered as examples only - not as production quality. I cannot offer advice regarding any other c/c++ compiler/IDE or incompatibilities with VS. You are ultimately responsible for the effects of your programs and the integrity of the machines they run on. Anything I post, code snippets, advice, etc is licensed as Public Domain https://creativecommons.org/publicdomain/zero/1.0/ and can be used without reference or acknowledgement. Also note that I only provide advice and guidance via the forums - and not via private messages!
C++23 Compiler: Microsoft VS2022 (17.6.5)
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