C语言数组

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

int main() {

    int32_t len = 10;
    int32_t arr[len];//arr[0] 访问数组第一个元素
    // clear array 清除数组 C中数组被创建时会有内存数据
    for (int a = 0; a < len; a++) {
        arr[a] = 0;
    }
    for (int32_t i = 0; i < len; i++) {
        printf("index %d,and value is %d\n", i, arr[i]);
    }


    //数组初始化
    int arra[] = {1, 3, 4, 5, 8, 9};
    for (int i = 0; i < 6; ++i) {
        printf("%d\n", arra[i]);
    }


    //创建二维数组
    int array[3][4];
    //clear arr
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 4; j++) {
            array[i][j] = 0;
        }
    }
    printf("%d\n", array[1][1]);
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 4; j++) {
            printf("index(%d,%d),%d\n", i, j, array[i][j]);
        }
    }

    //定义初始化
    int array34[3][4] = {{1, 2,  3,  4},
                         {5, 6,  7,  8},
                         {9, 10, 11, 12}};
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 4; j++) {
            printf("index(%d,%d),%d\n", i, j, array34[i][j]);
        }
    }

    //字符数组
    char str[10] = {'H', 'e', 'l', 'l', 'o', '\0'};//  \0  此时系统认为字符串结尾
    printf("String length : %ld，and string is %s\n", strlen(str), str);
    memset(str, 0, 10);//字符数组清零
    printf("String length : %ld，and string is %s\n", strlen(str), str);

    //遍历
    char string[] = "Hello World";
    for (int i = 0; i < 11; ++i) {
        printf("(index:%d)%c\n", i, string[i]);
    }
    return 0;
}