find 12

t9e10.find12.cpp

// t9e10.find12.cpp
// juanfc 2023-11-14
// https://gist.github.com/juanfal/0de9ce7af220a1d3fb59a3bb983b7d5d

#include <iostream>
#include <array>
using namespace std;

// consts
const int N=5;

// types
typedef array<float,N> TVec;

// prototypes
void writeArr(TVec a);
int find12(TVec a);

int main()
{
    TVec a = {{3, 1, 2, 3, 4}};
    writeArr(a); cout << endl;
    cout << "12 is at: "
         << find12(a) << endl;
    a = (TVec){{3, 2, 2, 2, 1}};
    writeArr(a); cout << endl;
    cout << "12 is at: "
         << find12(a) << endl;
    return 0;
}

void swap(int& a, int& b);

int find12(TVec a)
{
    int i = 1;
    while (i < N and not (a[i-1] == 1 and a[i]==2))
        ++i;
    return (i==N)? -1: i-1;
}

void writeArr(TVec a)
{
    for (int i = 0; i < N; ++i)
        cout << a[i] << " ";
}

void swap(int& a, int& b)
{
    int t = a;
    a = b; b = t;
}