CODEWITHSUNDEEP
ccharintscanf
Tudor
Tudor

Reputation: 1578

reading a number into a char

what happens if I read an integer like 20,30,10000...9999 into variable a ? it only prints the first digit in the number that I've read...why is that ? for example if I read 123, on the screen it prints 1. Isn't it supposed to convert the integer 123 into it's equivalent ASCII character representation ?

#include <stdio.h>

int main() {

    char a;

    scanf("%c", &a);
    printf("%c", a);

    return 0;
}

This is an exam question from C language.

Upvotes: 0

Views: 13666

Answers (3)

HelloWorld123456789
HelloWorld123456789

Reputation: 5359

No, it will read only the first character into the char variable. How can a char variable store more than one character at an instant? It can't.

So if you want the ASCII value, input as an integer instead.

int a;
scanf("%d", &a); // suppose input is 65
printf("%c", a); // prints 'A'
printf("%d", a); // prints 65

Whereas

char a;
scanf("%c", &a); // suppose input is 65
printf("%c", a); // prints '6'
printf("%d", a); // prints 54 which is the ASCII value of '6'

Upvotes: 1

unwind
unwind

Reputation: 399833

No, it reads the character, which is represented by the machine as a small integer, into the variable.

If you enter 100 (the number 100, three keypresses and thus three characters), it will only store the first character of that, i.e. the leading 1.

If you wanted to convert a number to an actual integer, you should use %d and an int variable of course.

Printing with %c will print back a single character, by interpreting the small integer value as a character (rather than as an integer). So for an input of 100 you will see 1 printed back out, i.e. the character that represents the decimal digit one.

If you want to print out the numeric representation of the character you read in, scan with %c but print with %d, and cast the char to (int) in the printf() call.

Upvotes: 3

chfumero
chfumero

Reputation: 1147

The problem is that %c parse a char for console input. From a number like 123 it take only the first letter and dispose the rest. The way to parse a int value is using %d on the scanf function.

Upvotes: 1

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