C语言，统计二维字符数组中字母，数字，空格，其他字符的个数，用循环，输入每行的字符串

可以使用两层循环，第一层循环遍历输入的每一行字符串，第二层循环遍历当前行字符串的每一个字符，然后使用if-else语句进行分类统计。

具体代码如下：

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

int main() {
    char arr[100][100];
    int n, letter_count, digit_count, space_count, other_count;

    printf("Enter the number of lines: ");
    scanf("%d", &n);

    getchar(); // 吃掉输入数字后的回车符

    for (int i = 0; i < n; i++) {
        printf("Enter string %d: ", i+1);
        gets(arr[i]); // 获取当前行字符串
    }

    for (int i = 0; i < n; i++) {
        letter_count = digit_count = space_count = other_count = 0; // 每次循环前先清零

        for (int j = 0; j < strlen(arr[i]); j++) {
            if (arr[i][j] >= 'a' && arr[i][j] <= 'z' || arr[i][j] >= 'A' && arr[i][j] <= 'Z') {
                letter_count++;
            } else if (arr[i][j] >= '0' && arr[i][j] <= '9') {
                digit_count++;
            } else if (arr[i][j] == ' ') {
                space_count++;
            } else {
                other_count++;
            }
        }

        printf("Line %d:\n", i+1);
        printf("Letter count: %d\n", letter_count);
        printf("Digit count: %d\n", digit_count);
        printf("Space count: %d\n", space_count);
        printf("Other count: %d\n", other_count);
    }

    return 0;
}

示例输入：

Enter the number of lines: 3
Enter string 1: Hello World!
Enter string 2: 12345 abcdefg
Enter string 3: ^&$#) 

输出结果：

Line 1:
Letter count: 10
Digit count: 0
Space count: 1
Other count: 1
Line 2:
Letter count: 7
Digit count: 5
Space count: 1
Other count: 0
Line 3:
Letter count: 0
Digit count: 0
Space count: 0
Other count: 6