C语言编程练习题：第一期

练习题1： 编写一个程序，计算并输出两个整数之和。

#include <stdio.h>

int main() {
    int num1, num2;
    
    printf("Enter two integers: ");
    scanf("%d %d", &num1, &num2);
    
    int sum = num1 + num2;
    printf("The sum of %d and %d is %d\n", num1, num2, sum);
    
    return 0;
}

练习题2： 编写一个程序，判断用户输入的年份是否为闰年。闰年的条件是：能被4整除但不能被100整除，或者能被400整除。

#include <stdio.h>

int main() {
    int year;
    
    printf("Enter a year: ");
    scanf("%d", &year);
    
    if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
        printf("%d is a leap year.\n", year);
    } else {
        printf("%d is not a leap year.\n", year);
    }
    
    return 0;
}

练习题3： 编写一个程序，计算并输出给定整数数组的所有元素之和。

#include <stdio.h>

int main() {
    int arr[] = {10, 20, 30, 40, 50};
    int n = sizeof(arr) / sizeof(arr[0]);
    int sum = 0;
    
    for (int i = 0; i < n; i++) {
        sum += arr[i];
    }
    
    printf("The sum of all elements in the array is %d\n", sum);
    
    return 0;
}

练习题4： 编写一个程序，实现字符串反转功能。

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

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

int main() {
    char str[100];
    printf("Enter a string: ");
    fgets(str, sizeof(str), stdin);
    
    str[strcspn(str, "\n")] = '\0'; // Remove trailing newline
    
    reverse(str);
    printf("Reversed string: %s\n", str);
    
    return 0;
}

练习题5： 编写一个程序，找出给定整数数组中的最大值和最小值。

#include <stdio.h>

int main() {
    int arr[] = {9, 7, 8, 6, Ⅰ1, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    int max = arr[0], min = arr[0];
    
    for (int i = 1; i < n; i++) {
        if (arr[i] > max) {
            max = arr[i];
        }
        if (arr[i] < min) {
            min = arr[i];
        }
    }
    
    printf("The maximum value in the array is %d\n", max);
    printf("The minimum value in the array is %d\n", min);
    
    return 0;
}