Returning the minimum of a vector

[Aquila]

Hello all.

I have the two functions below and their corresponding main function.

Function 1:

int maxofVec(int myarr[])
{
    size_t len=sizeof(myarr)/sizeof(myarr[0]);
    int minV=myarr[0];
    for(int i=1;i<len;i++)
    {
        if(myarr[i]<minV)
           {minV=myarr[i];}
    }

   return minV;
}

int main()
{
    int myarray[]={12,4,5,90,10,3,40,10,10,2,1,101,10};
    cout<<"\nThe minimum of the above is :"<<maxofVec(myarray);
    return 0;
}

Function 2:

int maxofVec(int myarr[], int len)
{

    int minV=myarr[0];
    for(int i=1;i<len;i++)
    {
        if(myarr[i]<minV)
           {minV=myarr[i];}
    }

   return minV;
}



int main()
{
    int myarray[]={12,4,5,90,10,3,40,10,10,2,1,101,10};
    int len=(int)sizeof(myarray)/sizeof(myarray[0]);
    cout<<"\nThe minimum of the above is :"<<maxofVec(myarray,len);
    return 0;
}

Function 1 is returning the first array element, instead of the minimum element, while function 2 gives the minimum as expected. What could be wrong with function 1, is anything wrong with my use of sizeof().

The kind response of the vets will be appreciated.

[shacktar]

What could be wrong with function 1, is anything wrong with my use of sizeof().

Essentially, yes. When you pass an array into a function, its type changes. In main(), myarray is of type int[] or "array of int", so the sizeof operator will return the total size of all its elements in bytes. When that array gets passed into maxOfVec, its type becomes int* or "pointer to int", despite that the function's signature would suggest otherwise.

The first function is returning the first element because len is evaluating to 1 since sizeof(myarr) would be the size of one pointer (probably 4 bytes on your system). Passing in the length would be the correct approach in this case.

Also, this example doesn't use a "vector" though using one would reduce some complexity here (you could ask a std::vector for its size directly).

[Aquila]

Thank you and well said @shacktar.