isdigit() 问题； - scanf 验证器

Question

我要看C语言的字符串是全是字母还是全是数字

我的代码：

char Name[50];
int flag = 0;
int charString = 0;

printf("Please insert your name\n");
scanf("%[^ A-Z\n]",Name);

while (Name[charString]){
flag = isdigit(Name[charString]);

    while(flag){
        getchar();
        printf("ERROR! Please insert only letters");
        scanf("%[^ A-Z\n]",I.Nome);
    }
charString++;
}

Answer 1

使用"[^ A-Z\n]"排除大写字符，可以排除数字但做"[^ A-Z0-9\n]".

然后检查输入是否有效只需检查 scanf() returns 1

if (scanf("%[^ A-Z0-9\n]", Name) != 1)
{
    printf("Invalid Input!\n");
    /* do something about it */
}

Answer 2

试试这个

#include <stdio.h>

int main(void){
    char Name[50], nl=0;
    int stat;

    printf("Please insert your name\n");
    stat=scanf("%49[a-z]%c", Name, &nl);

    while(stat != 2 || nl != '\n'){
        while(getchar() != '\n');//drop upto newline
        printf("ERROR! Please insert only letters\n");
        stat=scanf("%49[a-z]%c", Name, &nl);
    }
    printf("your name is '%s'\n", Name);
    return 0 ;
}

Answer 3

如果您不想让用户用户输入数字，请禁用数字输入。这将忽略除字母或 space 之外的所有键，甚至不显示它们。

#include <stdio.h>
#include <conio.h>
#include <ctype.h>
void main()
{
   char name[50];
   char key=0;
   int i=0;
   while(1)
  {
     key=getch();           //get input from keyboard
    if(!key)
      getch();              //if pressed key is a extended ASCII key ignore it

    if(isalpha(key)||key==32)
      putch(name[i++]=key); //if pressed key is a-z or A-Z or space, display it and add to name.
    else if( key==8 && i>=0) //if backspace is pressed erase a character before it
    {
      printf("%c%c%c",8,32,8);
      i--;
    }
    else if(key==13)       //if enter key is pressed end the loop
    break;
  }
  name[i]='[=10=]';//end of the string
}

isdigit() 问题； - scanf 验证器

Issue with isdigit(); - scanf validator

c

string

validation