给定一个字符串 str[]，任务是检查字符串是否包含任何特殊字符，如果字符串有特殊字符，则打印“字符串不被接受”，否则打印“字符串被接受”。

特殊字符是那些既不是数字也不是字母的字符，即 - !@#$%^&*()+=-][‘;/.,{}|:"?`~

因此，在C编程语言中，我们将使用if-else方法来解决问题。

输入 - str[] = {"tutorials-point"}

输出 - 字符串不被接受

输入 - str[] = {"tutorialspoint"}

输出 - 字符串被接受

以下是解决问题的方法：

• 遍历整个字符串。

• 查找特殊字符，如果字符串中存在特殊字符，则打印“字符串不被接受并中断”。否则，打印字符串被接受。

其他方法

如果我们在Java或任何其他支持正则表达式概念的语言中编码，那么我们将使用正则表达式来检查给定字符串中是否存在它们。这不仅是一种简单的方法，而且速度快。

算法

Start
In function int special_character(char str[], int n)
   Step 1→ initialize i and flag and set flag as 0
   Step 2→ Loop For i = 0 and i < n and ++i
      If(str[i] == '!' || str[i] == '@' || str[i] == '#' || str[i] == '$'
      || str[i] == '%' || str[i] == '^' || str[i] == '&' || str[i] == '*'
      || str[i] == '(' || str[i] == ')' || str[i] == '-' || str[i] == '{'
      || str[i] == '}' || str[i] == '[' || str[i] == ']' || str[i] == ':'
      || str[i] == ';' || str[i] == '"' || str[i] == ''' || str[i] == '<'
      || str[i] == '>' || str[i] == '.' || str[i] == '/' || str[i] == '?'
      || str[i] == '~' || str[i] == '`' then
         Print "String is not allowed”
            Set flag as 1
         break
   Step 3→ If flag == 0 then,
      Print "string is accepted”
In function int main(int argc, char const *argv[])
   Step 1→ Declare and set str[] as {"Tutorials-point"}
   Step 2→ set n as strlen(str)
   Step 3→ special_character(str, n)
Stop

示例

实时演示

#include <stdio.h>
#include <string.h>
int special_character(char str[], int n){
   int i, flag = 0;
   for (i = 0; i < n; ++i){
      //checking each character of the string for special character.
      if(str[i] == '!' || str[i] == '@' || str[i] == '#' || str[i] == '$'
      || str[i] == '%' || str[i] == '^' || str[i] == '&' || str[i] == '*'
      || str[i] == '(' || str[i] == ')' || str[i] == '-' || str[i] == '{'
      || str[i] == '}' || str[i] == '[' || str[i] == ']' || str[i] == ':'
      || str[i] == ';' || str[i] == '"' || str[i] == ''' || str[i] == '<'
      || str[i] == '>' || str[i] == '.' || str[i] == '/' || str[i] == '?'
      || str[i] == '~' || str[i] == '`' ){
         printf("String is not allowed<p>");
         flag = 1;
         break;
      }
   }
   //if there is no special charcter
   if (flag == 0){
      printf("string is accepted</p><p>");
   }
   return 0;
}
int main(int argc, char const *argv[]){
   char str[] = {"Tutorials-point"};
   int n = strlen(str);
   special_character(str, n);
   return 0;
}</p>

输出

如果运行上述代码，将生成以下输出−

String is not allowed