Finding a specific number in a random array? - c++

Question

Below is the code I've written to find the largest and smallest number in an array of 100 integers(which are random).
My question is for the user to enter a number and find the location of the number the user entered. For example: "The number 230 was found at array location 34" or something like that.
How do I go about this question? My attempt looks something like
cout << "Enter #: ";
cin >> Input;
if(1){
for (int i = 0; i < 100 : i++){
if (Input == arr[i]
cout << "Location: " << i << endl;
} else
cout << "Input was not found ";
#include "stdafx.h"
#include <ctime>
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
int main() {
int small, big;
int arr[100];
srand(time(0));
for(int i=0; i < 100; i++) {
arr[i] = rand() % 1000;
}
for(int i=0; i < 100; i++) {
cout << arr[i] << " ";
}
cout << endl;
big = small = arr[0];
for (int i = 0; i < 100; i++) {
if (arr[i] > big) {
big = arr[i];
}
if(arr[i] < small) { // compares smallest value with current element
small = arr[i];
}
}
}

Answer 1

A simple (and not ideal) solution is to loop over the array until the desired number is found. Something along the lines of:
const int N = 100;
int arr[N];
for (int i = 0; i < N; i++) {
arr[i] = rand() % 1000;
}
// Number to search for
int target = 11;
// Single loop searching for target
int index = -1;
for (int i = 0; i < N; i++) {
if (arr[i] == target) {
index = i;
break; // break when target found
}
}
if (index != -1) {
cout << "Found at " << index << "\n";
}
else {
cout << "Not Found\n";
}
However, you should use a vector whenever possible instead of an array. One benefit of using a vector is the ability to use the standard library find function.
#include <vector>
#include <algorithm>
#include <iostream>
#include <cstdlib>
using namespace std;
int main() {
vector<int> vec;
// fill vec with random numbers
for (int i = 0; i < 100; i++) {
int random_number = rand() % 1000;
vec.push_back(random_number); // adds random_number to end of vec
}
// Number we are searching for
int target = 7;
// find an iterator pointing to target if it exists
// else it will be vec.end()
auto it = find(vec.begin(), vec.end(), target);
if (it != vec.end()) {
// find distance of it from beggining of vector
// i.e. vec[index] == target
int index = distance(vec.begin(), it);
cout << "Found " << target << " at " << index << "\n";
}
else {
cout << "Not Found\n";
}
}