下面是一个使用C语言实现的几个常见算法示例，包括排序算法（冒泡排序、快速排序）、查找算法（二分查找）以及递归算法（斐波那契数列）。
1. 冒泡排序（Bubble Sort）
#include <stdio.h>void bubbleSort(int arr[], int n) {for (int i = 0; i < n-1; i++) {for (int j = 0; j < n-i-1; j++) {if (arr[j] > arr[j+1]) {// 交换元素int temp = arr[j];arr[j] = arr[j+1];arr[j+1] = temp;}}}
}int main() {int arr[] = {64, 34, 25, 12, 22, 11, 90};int n = sizeof(arr)/sizeof(arr[0]);bubbleSort(arr, n);printf("Sorted array: \n");for (int i = 0; i < n; i++) {printf("%d ", arr[i]);}return 0;
}
2. 快速排序（Quick Sort）
#include <stdio.h>void swap(int* a, int* b) {int t = *a;*a = *b;*b = t;
}int partition(int arr[], int low, int high) {int pivot = arr[high];int i = (low - 1);for (int j = low; j <= high - 1; j++) {if (arr[j] < pivot) {i++;swap(&arr[i], &arr[j]);}}swap(&arr[i + 1], &arr[high]);return (i + 1);
}void quickSort(int arr[], int low, int high) {if (low < high) {int pi = partition(arr, low, high);quickSort(arr, low, pi - 1);quickSort(arr, pi + 1, high);}
}int main() {int arr[] = {10, 7, 8, 9, 1, 5};int n = sizeof(arr)/sizeof(arr[0]);quickSort(arr, 0, n-1);printf("Sorted array: \n");for (int i = 0; i < n; i++) {printf("%d ", arr[i]);}return 0;
}
3. 二分查找（Binary Search）
#include <stdio.h>int binarySearch(int arr[], int l, int r, int x) {while (l <= r) {int m = l + (r - l) / 2;if (arr[m] == x)return m;if (arr[m] < x)l = m + 1;elser = m - 1;}return -1;
}int main() {int arr[] = {2, 3, 4, 10, 40};int n = sizeof(arr)/sizeof(arr[0]);int x = 10;int result = binarySearch(arr, 0, n-1, x);if (result == -1)printf("Element is not present in array\n");elseprintf("Element is present at index %d\n", result);return 0;
}
4. 斐波那契数列（Fibonacci Sequence）
#include <stdio.h>int fibonacci(int n) {if (n <= 1)return n;return fibonacci(n-1) + fibonacci(n-2);
}int main() {int n = 10;printf("Fibonacci sequence up to %d terms: \n", n);for (int i = 0; i < n; i++) {printf("%d ", fibonacci(i));}return 0;
}
5. 插入排序（Insertion Sort）
#include <stdio.h>void insertionSort(int arr[], int n) {int i, key, j;for (i = 1; i < n; i++) {key = arr[i];j = i - 1;while (j >= 0 && arr[j] > key) {arr[j + 1] = arr[j];j = j - 1;}arr[j + 1] = key;}
}int main() {int arr[] = {12, 11, 13, 5, 6};int n = sizeof(arr)/sizeof(arr[0]);insertionSort(arr, n);printf("Sorted array: \n");for (int i = 0; i < n; i++) {printf("%d ", arr[i]);}return 0;
}
6. 选择排序（Selection Sort）
#include <stdio.h>void swap(int *xp, int *yp) {int temp = *xp;*xp = *yp;*yp = temp;
}void selectionSort(int arr[], int n) {int i, j, min_idx;for (i = 0; i < n-1; i++) {min_idx = i;for (j = i+1; j < n; j++)if (arr[j] < arr[min_idx])min_idx = j;swap(&arr[min_idx], &arr[i]);}
}int main() {int arr[] = {64, 25, 12, 22, 11};int n = sizeof(arr)/sizeof(arr[0]);selectionSort(arr, n);printf("Sorted array: \n");for (int i = 0; i < n; i++) {printf("%d ", arr[i]);}return 0;
}
7. 归并排序（Merge Sort）
#include <stdio.h>
#include <stdlib.h>void merge(int arr[], int l, int m, int r) {int i, j, k;int n1 = m - l + 1;int n2 = r - m;int L[n1], R[n2];for (i = 0; i < n1; i++)L[i] = arr[l + i];for (j = 0; j < n2; j++)R[j] = arr[m + 1 + j];i = 0;j = 0;k = l;while (i < n1 && j < n2) {if (L[i] <= R[j]) {arr[k] = L[i];i++;} else {arr[k] = R[j];j++;}k++;}while (i < n1) {arr[k] = L[i];i++;k++;}while (j < n2) {arr[k] = R[j];j++;k++;}
}void mergeSort(int arr[], int l, int r) {if (l < r) {int m = l + (r - l) / 2;mergeSort(arr, l, m);mergeSort(arr, m + 1, r);merge(arr, l, m, r);}
}int main() {int arr[] = {12, 11, 13, 5, 6, 7};int arr_size = sizeof(arr)/sizeof(arr[0]);printf("Given array is \n");for (int i = 0; i < arr_size; i++)printf("%d ", arr[i]);mergeSort(arr, 0, arr_size - 1);printf("\nSorted array is \n");for (int i = 0; i < arr_size; i++)printf("%d ", arr[i]);return 0;
}
8. 堆排序（Heap Sort）
#include <stdio.h>void swap(int *a, int *b) {int temp = *a;*a = *b;*b = temp;
}void heapify(int arr[], int n, int i) {int largest = i;int left = 2 * i + 1;int right = 2 * i + 2;if (left < n && arr[left] > arr[largest])largest = left;if (right < n && arr[right] > arr[largest])largest = right;if (largest != i) {swap(&arr[i], &arr[largest]);heapify(arr, n, largest);}
}void heapSort(int arr[], int n) {for (int i = n / 2 - 1; i >= 0; i--)heapify(arr, n, i);for (int i = n - 1; i > 0; i--) {swap(&arr[0], &arr[i]);heapify(arr, i, 0);}
}int main() {int arr[] = {12, 11, 13, 5, 6, 7};int n = sizeof(arr)/sizeof(arr[0]);heapSort(arr, n);printf("Sorted array is \n");for (int i = 0; i < n; i++)printf("%d ", arr[i]);return 0;
}
9. 线性查找（Linear Search）
#include <stdio.h>int linearSearch(int arr[], int n, int x) {for (int i = 0; i < n; i++) {if (arr[i] == x)return i;}return -1;
}int main() {int arr[] = {2, 3, 4, 10, 40};int n = sizeof(arr)/sizeof(arr[0]);int x = 10;int result = linearSearch(arr, n, x);if (result == -1)printf("Element is not present in array\n");elseprintf("Element is present at index %d\n", result);return 0;
}
10. 递归求阶乘（Factorial）
#include <stdio.h>int factorial(int n) {if (n == 0)return 1;return n * factorial(n - 1);
}int main() {int n = 5;printf("Factorial of %d is %d\n", n, factorial(n));return 0;
}
11. 递归求最大公约数（GCD）
#include <stdio.h>int gcd(int a, int b) {if (b == 0)return a;return gcd(b, a % b);
}int main() {int a = 60, b = 48;printf("GCD of %d and %d is %d\n", a, b, gcd(a, b));return 0;
}
12. 递归求幂（Power）
#include <stdio.h>double power(double base, int exp) {if (exp == 0)return 1;if (exp > 0)return base * power(base, exp - 1);return 1 / power(base, -exp);
}int main() {double base = 2.0;int exp = 3;printf("%.2f^%d = %.2f\n", base, exp, power(base, exp));return 0;
}
13. 递归求数组和（Array Sum）
#include <stdio.h>int arraySum(int arr[], int n) {if (n <= 0)return 0;return arr[n-1] + arraySum(arr, n-1);
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);printf("Sum of array is %d\n", arraySum(arr, n));return 0;
}
14. 递归求数组最大值（Array Max）
#include <stdio.h>int arrayMax(int arr[], int n) {if (n == 1)return arr[0];int max = arrayMax(arr, n-1);return (arr[n-1] > max) ? arr[n-1] : max;
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);printf("Max of array is %d\n", arrayMax(arr, n));return 0;
}
15. 递归求数组最小值（Array Min）
#include <stdio.h>int arrayMin(int arr[], int n) {if (n == 1)return arr[0];int min = arrayMin(arr, n-1);return (arr[n-1] < min) ? arr[n-1] : min;
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);printf("Min of array is %d\n", arrayMin(arr, n));return 0;
}
16. 递归求数组平均值（Array Average）
#include <stdio.h>double arrayAverage(int arr[], int n) {if (n == 1)return arr[0];return (arr[n-1] + (n-1) * arrayAverage(arr, n-1)) / n;
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);printf("Average of array is %.2f\n", arrayAverage(arr, n));return 0;
}
17. 递归求数组逆序（Array Reverse）
#include <stdio.h>void arrayReverse(int arr[], int start, int end) {if (start >= end)return;int temp = arr[start];arr[start] = arr[end];arr[end] = temp;arrayReverse(arr, start+1, end-1);
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);arrayReverse(arr, 0, n-1);printf("Reversed array is \n");for (int i = 0; i < n; i++)printf("%d ", arr[i]);return 0;
}
18. 递归求数组是否有序（Array Sorted）
#include <stdio.h>int isArraySorted(int arr[], int n) {if (n == 1)return 1;if (arr[n-1] < arr[n-2])return 0;return isArraySorted(arr, n-1);
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);if (isArraySorted(arr, n))printf("Array is sorted\n");elseprintf("Array is not sorted\n");return 0;
}
19. 递归求数组是否包含元素（Array Contains）
#include <stdio.h>int arrayContains(int arr[], int n, int x) {if (n == 0)return 0;if (arr[n-1] == x)return 1;return arrayContains(arr, n-1, x);
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);int x = 3;if (arrayContains(arr, n, x))printf("Array contains %d\n", x);elseprintf("Array does not contain %d\n", x);return 0;
}
20. 递归求数组元素个数（Array Count）
#include <stdio.h>int arrayCount(int arr[], int n, int x) {if (n == 0)return 0;if (arr[n-1] == x)return 1 + arrayCount(arr, n-1, x);return arrayCount(arr, n-1, x);
}int main() {int arr[] = {1, 2, 3, 4, 5, 3};int n = sizeof(arr)/sizeof(arr[0]);int x = 3;printf("Array contains %d occurrences of %d\n", arrayCount(arr, n, x), x);return 0;
}
21. 递归求数组元素位置（Array Index）
#include <stdio.h>int arrayIndex(int arr[], int n, int x) {if (n == 0)return -1;if (arr[n-1] == x)return n-1;return arrayIndex(arr, n-1, x);
}int main() {int arr[] = {1, 2, 3, 4, 5};int n = sizeof(arr)/sizeof(arr[0]);int x = 3;int index = arrayIndex(arr, n, x);if (index == -1)printf("Array does not contain %d\n", x);elseprintf("Array contains %d at index %d\n", x, index);return 0;
}
