Largest Element in an Array

CSC-115 · Semester I · C Programming

beginner20 minAvailable

Cin-browser interpreter · runs locally

#include <stdio.h>

int main() {
  int a[5] = {14, 27, 9, 31, 18};
  int largest = a[0];
  for (int i = 1; i < 5; i++) {
    if (a[i] > largest) largest = a[i];
  }
  printf("Largest element = %d\n", largest);
  return 0;
}

12 lines

Output

Write some code, then press Run. Stdout and errors appear here.

Lab brief

Objective

Store a list of numbers in a one-dimensional array and find the largest value by traversing it.

Theory & concepts

To find the largest element, assume the first element is the largest, then scan the rest of the array. Whenever a later element is bigger, it becomes the new maximum. After the loop, the 'current largest' holds the true maximum.

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One pass to find the largest element

int max = arr[0];
for (int i = 1; i < n; i++)
    if (arr[i] > max)
        max = arr[i];

Why start at arr[0]?

Initializing max to 0 would fail for all-negative arrays - 0 would win every comparison. Starting from arr[0] guarantees the answer is always one of the actual elements.

Prerequisites

Lesson: One-dimensional arrays
Lesson: Array initialization and traversal

Instructions

1Declare an integer array of size 5.
2Read 5 numbers into the array with a for loop and scanf.
3Set a variable max to arr[0].
4Loop from index 1 to 4, updating max whenever arr[i] > max.
5Print the value of max and verify with sample data.

Tasks

Implement the search
Read 5 numbers and print the largest one.
Verify with sample data
Input 12 45 3 78 30 - largest should be 78.
Find the smallest too
Adapt the same pattern to find and print the smallest element.
Handle the edge case
What should the program print if all five numbers are negative? Confirm it still works.

Self-check

The program reads all 5 values before searching.
The largest value is correct for both positive and negative inputs.
The loop indices stay within the array bounds.
The student can explain why max starts at arr[0] rather than 0.

Environment

editorstandard inputstdout consoletest cases

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