编写一个函数，从控制台逐行读取并打印每行加载的字符数。

Posted 2021-03-19

写一个函数，从控制台逐行读取并打印每行的字符数，读取的行的最大长度应该是20个字符。

我有一些只是通过循环和打印一遍又一遍的输入字符串.我有问题 - 打印每个用户输入后的字符数，并设置最大字符输入为20的考试。谁能帮帮我？

     char str[str_size];
    int alp, digit, splch, i;
    alp = digit = splch = i = 0;


    printf("\n\nCount total number of alphabets, digits and special characters :\n");
    printf("--------------------------------------------------------------------\n");
    do {
        printf("Input the string : ");

        fgets(str, sizeof str, stdin);

    } while (str[i] != '\0');
        if ((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z'))
        {
            alp++;

        }
        else if (str[i] >= '0' && str[i] <= '9')
        {
            digit++;
        }
        else
        {
            splch++;
        }

        i++;

printf("Number of Alphabets in the string is : %d\n", alp + digit + splch);


}

答案

我不明白你做什么用 do while 循环。所以我只是为你的情况提出另一个循环。我不确定，但希望这个代码是你想要的。

int main() {
    char str[22];
    int alp, digit, splch, i;
    printf("\n\nCount total number of alphabets, digits and special characters :\n");
    printf("--------------------------------------------------------------------\n");
    printf("Input the string : ");
    while (fgets(str, sizeof str, stdin)){
        alp = digit = splch = 0;
        for (i = 0; i < strlen(str); i++ ) {
            if ((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z'))
            {
                alp++;
            }
            else if (str[i] >= '0' && str[i] <= '9')
            {
                digit++;
            }
            else if(str[i] != '\n')
            {
                splch++;
            }
        }
        printf("alp = %d, digit = %d, splch = %d\n", alp, digit, splch);
        printf("Input the string : ");
    }
    return 0;
}

OT，为了确定α或数字，你可以使用 isdigit() 和 isalpha() 函数。比你代码里用的东西简单多了。

另一答案

似乎程序可以这样看

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

int main(void) 
{
    enum { str_size = 22 };
    char str[str_size];

    puts( "\nCount total number of alphabets, digits and special characters");
    puts( "--------------------------------------------------------------");

    while ( 1 )
    {
        printf( "\nInput a string less than or equal to %d characters (Enter - exit): ",
                str_size - 2 );

        if ( fgets( str, str_size, stdin ) == NULL || str[0] == '\n' ) break;

        unsigned int alpha = 0, digit = 0, special = 0;

        // removing the appended new line character by fgets
        str[ strcspn( str, "\n" ) ] = '\0';

        for ( const char *p = str; *p != '\0'; ++p )
        {
            unsigned char c = *p;

            if ( isalpha( c ) ) ++alpha;
            else if ( isdigit( c ) ) ++digit;
            else ++special;
        }

        printf( "\nThere are %u letters, %u digits and %u special characters in the string\n",
                alpha, digit, special );    
    }

    return 0;
}

程序的输出可能是这样的

Count total number of alphabets, digits and special characters
--------------------------------------------------------------

Input a string less than or equal to 20 characters (Enter - exit): April, 22, 2020

There are 5 letters, 6 digits and 4 special characters in the string

Input a string less than or equal to 20 characters (Enter - exit): 

如果用户只按回车键，循环就会结束。

注意，程序将空白和标点符号视为特殊字符。