1. (简答题) Write a program to count the occurrences of each letter in an array of characters. Here is a sample run. ------------------------------------------------------ Enter the string : abcddcabae a occurs 3 times in the string, b occurs 2 times in the string, c occurs 2 times in the string, d occurs 2 times in the string, e occurs 1 times in the string,

以下是 C 语言代码实现，可以用来统计一个字符数组中每个字符的出现次数：

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

void count_occurrences(char string[]) {
    int freq[26] = {0}; // 初始化每个字母的出现次数为 0

    for (int i = 0; i < strlen(string); i++) {
        char c = string[i];
        if (c >= 'a' && c <= 'z') {
            freq[c - 'a']++; // 如果是小写字母，增加对应字母的出现次数
        } else if (c >= 'A' && c <= 'Z') {
            freq[c - 'A']++; // 如果是大写字母，增加对应字母的出现次数
        }
    }

    for (int i = 0; i < 26; i++) {
        if (freq[i] > 0) {
            printf("%c occurs %d times in the string.\n", 'a' + i, freq[i]);
        }
    }
}

int main() {
    char string[100];
    printf("Enter the string: ");
    fgets(string, 100, stdin); // 从标准输入中读取字符串

    count_occurrences(string);

    return 0;
}

运行结果：

Enter the string: abcddcabae
a occurs 3 times in the string.
b occurs 2 times in the string.
c occurs 2 times in the string.
d occurs 2 times in the string.
e occurs 1 times in the string.