分别统计字符串c中字母数字空格和其他字符出现的次数

你可以通过编程语言中的遍历和条件判断来分别统计字符串 `c` 中字母、数字、空格以及其他字符出现的次数。这里是一个简单的 Python 示例：

def count_chars(s):
    counts = {'letters': 0, 'digits': 0, 'spaces': 0, 'other': 0}

    for char in s:
        if char.isalpha():
            counts['letters'] += 1
        elif char.isdigit():
            counts['digits'] += 1
        elif char.isspace():
            counts['spaces'] += 1
        else:
            counts['other'] += 1

    return counts

# 使用示例
c = "Hello, World! This is a test string 123."
char_counts = count_chars(c)
print("Letters:", char_counts['letters'])
print("Digits:", char_counts['digits'])
print("Spaces:", char_counts['spaces'])
print("Other characters:", char_counts['other'])