CODEWITHSUNDEEP
cscanf
Lorenzo Imperatrice
Lorenzo Imperatrice

Reputation: 997

How to write '\n' from keyboard with scanf() in C

I'm new to C and I would like to know if it's possible to write into a string the character \n from the keyboard by using scanf() function.

The code that I'm using is this: (sorry for the Italian variables words)

void riempi_array_stringhe (char* stringhe[], int lunghezza_array)
{
    for (int i = 0; i < lunghezza_array; i++) {
        stringhe[i] = (char*) malloc(sizeof(char) * 100);
        printf("Insert a new string: ");
        scanf("%s", stringhe[i]);
    }
}

I tried type shift + enter, alt + enter, or to insert \n as input but not works at all.

Thanks in advance!

Upvotes: 0

Views: 444

Answers (1)

Andriy Berestovskyy
Andriy Berestovskyy

Reputation: 8534

There is a [ specifier. Quote from scanf(2)

[ — Matches a nonempty sequence of characters from the specified set of accepted characters; the next pointer must be a pointer to char, and there must be enough room for all the characters in the string, plus a terminating null byte.

Example:

#include <math.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
    char *str[10];

    for (int i = 0; i < 10; i++) {
        str[i] = (char *)malloc(sizeof(char) * 100);
        printf("Insert a new string: ");
        scanf("%[^~]", str[i]);
        printf("Your input: %s\n", str[i]);
    }
    return 0;
}

To end the input we should input ~ and then Enter or press Ctrl+D (EOF). We can specify other characters to terminate the input. For example, scanf("%[^X]", str[i]); will terminate the input after user inserts an X and then Enter.

Please note, to prevent your buffer overrun, you should always specify the width of the sequence equals to the buffer size minus one (for NUL character), i.e.:

scanf("%99[^~]", str[i]); // read no more than 99 symbols + NUL

Upvotes: 3

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