数组

 

一维数组:int,charfloat

一维数组的结构:类型修饰符 数组名[数组元素个数]=初始值;

注意事项:数组元素不能是变量,一般整型表达式.

数组的排序:冒泡排序法(交换两个变量的三种方法),,,,其他排序方法

字符数组:用双引号定义””,通常字符串是以结束但他不计入字符串长度

字符数组的几种类型:strlen  计算字符串长度

                                 strcpy  字符串拷贝

                                 strcat 字符串拼接

                                 strcmp 字符串比较(ASCII码)

字符数组 : 是结束的标志

//        char arr[6] = "hello";
//       
//        char name[20] = {'1','2','3'};
//        char name1[20] = "yuanxinfeng";
//        char name2[20] = "liuzhenyi";
//        char name3[20] = "wangmingwei";printf("%s %s %s %s ",name,name1,name2,name3);
//       
//        strlen 计算字符串的长度 每个字符串是以''作为结束 但是在计算字符串的时候,''是不算在内的
//       
//        char name[] = "赵成浩";
//        unsigned long length = strlen(name);
//       int length = (int)strlen(name);//(强制类型转换)
//        printf("%lu ",length);
//
//        char name1[] = "yuanxinfeng";
//        char name2[] = "liuzhenyi";
//        char name3[] = "wangmingwei";
//        unsigned long length1 = strlen(name1);
//        unsigned long length2 = strlen(name2);
//        unsigned long length3 = strlen(name3);
//        printf("%lu %lu %lu ",length1,length2,length3);
//
       
       //strcpy
//        char name[20] = "yuanxin";
//        char name1[] = "feng";
//        //第一个字符串是拷贝出来的字符串 第二个字符串是往里拷贝的字符串
//        strcpy(name1, name);
//        printf("%s ",name1);
        //strcat 字符串拼接
        //第一个参数是要被拼接的字符串,第二个参数是拼接上的字符串
        //注意:第一个参数,被拼接的字符串长度要足够长
//        strcat(name, name1);
//        printf("%s ",name);
       
        //字符串比较 第一个字符串 每个元素 与第二个字符串的每个元素进行比较
        //如果输出的是正数证明第一个字符串较大如果是负数证明第一个字符串较小,如果输出的是零证明两个字符串相等
        //差值是ASCII码表的差值;strcmp abc abd = -1
//        char arr1[] = "aab";
//        char arr2[] = "aaa";
//        printf("%d ",strcmp(arr1, arr2));
       
       
//        int count = 0;//用来计算空格
//        char word[] = "I love ios, I want an iphone6s!";
//        for (int i = 0; i < strlen(word); i++) {
//            if (word[i] == ' ') {
//                count++;
//            }
//        }

//        printf("%d ",count);

输入年月日计算天数:

      int year = 0;

        int month = 0;
        int day = 0;
        printf("请输入 年 月 日:");
        scanf("%d%d%d",&year,&month,&day);
        int daysInMonths[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
        if (year % 400 == 0 || (year % 4==0 && year % 100 != 0))
        {
            daysInMonths[1] = 29;
        }
        int totalDays = 0;
        for (int i = 0; i < month - 1; i++)
        {
            totalDays += daysInMonths[i];
        }
            totalDays += day;

            printf("%d ",totalDays);

星星题

int n = 0;
        printf("please input n :");
        scanf("%d",&n);
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < n - i; j++) {
                printf(" ");
            }
            for (int k = 1; k < 2 * i; k++) {
                printf("*");
            }
            printf(" ");
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < i; j++) {
                printf(" ");
            }
            for (int k = 0; k < (n - i) * 2 - 1; k++) {
                printf("*");
            }
            printf(" ");
        }
        printf(" ");
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < n - i; j++) {
                printf(" ");
            }
            printf("*");
            for (int k = 0; k < (i - 1)*2 -1; k++) {
                printf(" ");
            }
            if (i != 1) {
                printf("*");
            }
            printf(" ");
        }
        for (int i = 1; i < n; i++) {
            for (int j = 0; j < i; j++) {
                printf(" ");
            }
            printf("*");
            for (int k = 0; k < (n-1-i)*2 -1; k++) {
                printf(" ");
            }
            if (i != n-1) {
                printf("*");
            }
            printf(" ");
        }