高频面试题：一个字符串中每个字符出现的次数

def count_characters(input_string):
    char_count = {}
    
    # 遍历字符串，统计每个字符出现的次数
    for char in input_string:
        if char in char_count:
            char_count[char] += 1
        else:
            char_count[char] = 1
    
    return char_count

input_string = "hello world"
result = count_characters(input_string)

# 输出每个字符及其出现次数
for char, count in result.items():
    print(f"{char} : {count}")