使用 scanf 读取字符串作为输入

Question

I am new to C language and I am trying read a character and a string (a sentence; max-length 25) from a user.

Not sure what I am doing wrong in the following lines of code, its giving me an error "Segment Fault".

#include <stdio.h>

int main(){
    char * str[25];
    char car;

    printf("Enter a character: ");
    car = getchar();

    printf("Enter a sentence: ");
    scanf("%[^\n]s", &str);

    printf("\nThe sentence is %s, and the character is %s\n", str, car);

    return 0;
}

Thanks!

Answer 1

You have to make four changes:

1. Change

   char * str[25];

   to

   char str[25];

   as you want an array of 25 char s, not an array of 25 pointers to char .

2. Change

   char car;

   to

   int car;

   as getchar() returns an int , not a char .

3. Change

   scanf("%[^\\n]s", &str);

   to

   scanf( "%24[^\\n]", str);

   which tells scanf to

   1. Ignore all whitespace characters, if any.
   2. Scan a maximum of 24 characters (+1 for the Nul-terminator '\\0' ) or until a \\n and store it in str .

4. Change

   printf("\\nThe sentence is %s, and the character is %s\\n", str, car);

   to

   printf("\\nThe sentence is %s, and the character is %c\\n", str, car);

   as the correct format specifier for a char is %c , not %s .

Answer 2

str is an array of 25 pointers to char , not an array of char . So change its declaration to

char str[25];

And you cannot use scanf to read sentences--it stops reading at the first whitespace, so use fgets to read the sentence instead.

And in your last printf , you need the %c specifier to print characters, not %s . You also need to flush the standard input, because there is a '\\n' remaining in stdin , so you need to throw those characters out.

The revised program is now

#include <stdio.h>    
void flush();
int main()
{
    char str[25], car;

    printf("Enter a character\n");
    car = getchar();

    flush();

    printf("Enter a sentence\n");
    fgets(str, 25, stdin);

    printf("\nThe sentence is %s, and the character is %c\n", str, car);

    return 0;
}
void flush()
{
    int c;
    while ((c = getchar()) != '\n' && c != EOF)
        ;
}

Answer 3

// This is minimal change to your code to work

#include <stdio.h>

int main(){

    char car,str[25];

    printf("Enter a character: ");
    car = getchar();

    printf("Enter a sentence: ");
    scanf("%s", str);

    printf("\nThe sentence is %s, and the character is %c\n", str, car);

    return 0;
}