C语言作为一种基础且强大的编程语言，是许多编程学习者的入门语言。在C语言的学习过程中，掌握一些经典的考试程序不仅能够帮助考生顺利通过考试，还能够加深对C语言的理解，提升编程技能。以下是一些C语言考试中必背的程序，以及相应的解题思路和技巧。

1. 排序算法

1.1 冒泡排序

#include <stdio.h>

void bubbleSort(int arr[], int n) {
    int i, j, temp;
    for (i = 0; i < n-1; i++) {
        for (j = 0; j < n-i-1; j++) {
            if (arr[j] > arr[j+1]) {
                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]);
    printf("\n");
    return 0;
}

1.2 快速排序

#include <stdio.h>

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++;
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }
    int temp = arr[i + 1];
    arr[i + 1] = arr[high];
    arr[high] = temp;
    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]);
    printf("\n");
    return 0;
}

2. 字符串处理

2.1 字符串反转

#include <stdio.h>
#include <string.h>

void reverseString(char str[]) {
    int len = strlen(str);
    for (int i = 0; i < len / 2; i++) {
        char temp = str[i];
        str[i] = str[len - 1 - i];
        str[len - 1 - i] = temp;
    }
}

int main() {
    char str[] = "Hello, World!";
    printf("Original string: %s\n", str);
    reverseString(str);
    printf("Reversed string: %s\n", str);
    return 0;
}

2.2 字符串查找

#include <stdio.h>
#include <string.h>

int stringFind(char str[], char substr[]) {
    return strstr(str, substr) - str;
}

int main() {
    char str[] = "Hello, World!";
    char substr[] = "World";
    printf("Substring found at index: %d\n", stringFind(str, substr));
    return 0;
}

3. 数组操作

3.1 数组元素删除

#include <stdio.h>

void deleteElement(int arr[], int n, int index) {
    for (int i = index; i < n - 1; i++)
        arr[i] = arr[i + 1];
    n--;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr)/sizeof(arr[0]);
    deleteElement(arr, n, 2);
    printf("Array after deletion: ");
    for (int i = 0; i < n - 1; i++)
        printf("%d ", arr[i]);
    printf("\n");
    return 0;
}

通过学习和掌握这些C语言考试必背程序，你不仅能够提高自己的编程技能，还能够为将来的学习和工作打下坚实的基础。记住，编程是一项实践性很强的技能，只有通过不断的练习和尝试，你才能真正掌握它。祝你在C语言的学习道路上越走越远！