How to assign return value of a function into a variable in c++?

Question

i want to assign a returned value of a function into a Variable in C++, but the program is exit without any output.

int numberPosition = binarySearch(arr, num, searchNumber);

program output screenshot

Full code---

#include <iostream>
using namespace std;


int binarySearch(int arr[], int num, int searchNumber){
    int start=0, end=num;

    while(start<=end){
        int mid = (start+end) / 2;
        if(arr[mid] == searchNumber){
            return mid;
        }else if(arr[mid] <= searchNumber){
            start = mid+1;
        }else{
            end = mid-1;
        }
    }
    
    return -1;
}

int main(){
    
    int num, arr[num], searchNumber;
    cout<<"How many Elements u want to insert? \n";
    
    cin>>num;
    
    cout<<"\n Enter ut Numbers:- \n";
    for(int i=0; i<num; i++){
        cin>>arr[i];
    }
    
    cout<<"\n Enter the Number u want to search:- ";
    cin>>searchNumber;
    
    int numberPosition = binarySearch(arr, num, searchNumber);
    
    if(numberPosition){
        cout<<searchNumber<<" is founded at position: "<<numberPosition;
    }else{
        cout<<searchNumber<<" is Not Founded";
    }
    
    return 0;
}

Please edit this to include a minimal reproducible example. How do you expect people to help if we don't know how you've written `binarySearch`, `arr`, `num`, or `searchNumber`? — Nathan Pierson, Nov 21 '20 at 05:33
Assigning the returned value to a variable doesn't output that value. You probably want to do something like `#import ` and then after the line you included, do `std::cout << numberPosition << "\n";`. — crimson_penguin, Nov 21 '20 at 05:35
Does your code compile without [warnings](https://stackoverflow.com/questions/57842756/)? Those would be the first things to address. — JaMiT, Nov 21 '20 at 05:42
you need to declare the array with length num after you have taken the input of variable num. it's causing error because of that — aman kapoor, Nov 21 '20 at 05:43
ohh i make a simple mistake @amankapoor thnks it's works now... — Numan Ahmed, Nov 21 '20 at 05:53

score 0 · Answer 1 · answered Nov 21 '20 at 05:41

The return code I am able to see in your program screenshot is 3221225725. This return code means that your computer ran out of stack memory before the recursion limit was reached..

So, you still have infinite recursion somewhere in your code.

So I think in your function binarySearch(arr,num,searchNumber), You are recursively calling your function somewhere. As you didn't post the code of your function I can't help you on that where you made the mistake.

So make sure your Implementation is correct. The correct implementation of the binary search c++ function is

int binarySearch(int arr[], int l, int r, int x) 
{ 
    if (r >= l) { 
        int mid = l + (r - l) / 2; 

        if (arr[mid] == x) 
            return mid; 

        if (arr[mid] > x) 
            return binarySearch(arr, l, mid - 1, x); 

        return binarySearch(arr, mid + 1, r, x); 
    } 

    return -1; 
}

score 0 · Accepted Answer · answered Nov 21 '20 at 05:49

Here This code works. You need to declare the length of array with variable num after you have taken the input value of num.

#include <iostream>
using namespace std;


int binarySearch(int arr[], int num, int searchNumber){
int start=0, end=num;

while(start<=end){
    int mid = (start+end) / 2;
    if(arr[mid] == searchNumber){
        return mid;
    }else if(arr[mid] <= searchNumber){
        start = mid+1;
    }else{
        end = mid-1;
    }
}

return -1;
}

int main(){

int num, searchNumber;
cout<<"How many Elements u want to insert? \n";

cin>>num;
int arr[num];
cout<<"\n Enter ut Numbers:- \n";
for(int i=0; i<num; i++){
    cin>>arr[i];
}

cout<<"\n Enter the Number u want to search:- ";
cin>>searchNumber;

int numberPosition = binarySearch(arr, num, searchNumber);

if(numberPosition!=-1){
    cout<<searchNumber<<" is founded at position: "<<numberPosition;
}else{
    cout<<searchNumber<<" is Not Founded";
}

return 0;
}

How to assign return value of a function into a variable in c++?

2 Answers2