输出给定的字符串中字母、数字、空格和其他字符的个数

（1）编写main函数

#include <stdio.h>int main() {return 0;
}

（2）编写计数函数

#include <stdio.h>void count_chars(char *str) {int letters = 0; // 字母计数器int digits = 0; // 数字计数器int spaces = 0; // 空格计数器int others = 0; // 其他字符计数器// 判断并计数for (int i = 0; str[i] != '\0'; ++i) {if ((str[i] >= 'A' && str[i] <= 'Z') || (str[i] >= 'a' && str[i] <= 'z')) {letters++;} else if (str[i] >= '0' && str[i] <= '9') {digits++;} else if (str[i] == ' ') {spaces++;} else {others++;}}// 输出各种字符的个数printf("Letters:%d\n", letters);printf("Digits:%d\n", digits);printf("Spaces:%d\n", spaces);printf("Others:%d\n", others);
}int main() {return 0;
}

（3）编写main函数

#include <stdio.h>void count_chars(char *str) {int letters = 0; // 字母计数器int digits = 0; // 数字计数器int spaces = 0; // 空格计数器int others = 0; // 其他字符计数器// 判断并计数for (int i = 0; str[i] != '\0'; ++i) {if ((str[i] >= 'A' && str[i] <= 'Z') || (str[i] >= 'a' && str[i] <= 'z')) {letters++;} else if (str[i] >= '0' && str[i] <= '9') {digits++;} else if (str[i] == ' ') {spaces++;} else {others++;}}// 输出各种字符的个数printf("Letters:%d\n", letters);printf("Digits:%d\n", digits);printf("Spaces:%d\n", spaces);printf("Others:%d\n", others);
}int main() {char str[30];printf("Please enter the value of str: ");fgets(str, sizeof(str), stdin); // 使用 fgets 读取整行输入count_chars(str);return 0;
}