# 編寫程序以反轉數組或字符串 > 原文： [https://www.geeksforgeeks.org/write-a-program-to-reverse-an-array-or-string/](https://www.geeksforgeeks.org/write-a-program-to-reverse-an-array-or-string/) 給定一個數組（或字符串），任務是反轉數組/字符串。 **示例**： ``` Input : arr[] = {1, 2, 3} Output : arr[] = {3, 2, 1} Input : arr[] = {4, 5, 1, 2} Output : arr[] = {2, 1, 5, 4} ``` **迭代方式**： > 1）將開始和結束索引初始化為`start = 0`，`end = n-1` > 2）在循環中，將`arr[start]`與`arr[end]`交換，并如下更改開始和結束： > `start = start + 1`，`end = end – 1`  另一個反轉字符串的示例：  下面是上述方法的實現： ## C++ ```cpp // Iterative C++ program to reverse an array #include <bits/stdc++.h> using namespace std; /* Function to reverse arr[] from start to end*/ void rvereseArray(int arr[], int start, int end) { ????while (start < end) ????{ ????????int temp = arr[start];? ????????arr[start] = arr[end]; ????????arr[end] = temp; ????????start++; ????????end--; ????}? }????? /* Utility function to print an array */ void printArray(int arr[], int size) { ???for (int i = 0; i < size; i++) ???cout << arr[i] << " "; ???cout << endl; }? /* Driver function to test above functions */ int main()? { ????int arr[] = {1, 2, 3, 4, 5, 6}; ????int n = sizeof(arr) / sizeof(arr[0]);? ????// To print original array? ????printArray(arr, n); ????// Function calling ????rvereseArray(arr, 0, n-1); ????cout << "Reversed array is" << endl; ????// To print the Reversed array ????printArray(arr, n); ????return 0; } ```