在C中的数组中存储ASCII字符

Question

I am trying to make a random generator using ASCII characters and due to my minimal knowledge, I am having difficulty trying to identify the best way to go about making this random generator.

Currently, I have managed to make a simple array which currently holds 6 values.

#include <stdio.h>
#include <conio.h>

    int main()
{
    int i;

    int  array[255] = {1, 2, 3 , 4, 5, 6 };

    for(i = 0; i < 6; i++)
    {
        printf("%d", array[i]); /* Prints out all values declared in the array*/
    }

    return 0;
}

output: 123456

What I am currently stuck on now is trying to find out how to replace the numbers with ASCII characters. If anyone could help me figure this out, I would be very grateful.

Answer 1

Use character literals in the array elements, and print them with %c format.

#include <stdio.h>
#include <conio.h>

int main()
{
    int i;

    int  array[255] = {'1', '2', '3' , '4', '5', '6' };

    for(i = 0; i < 6; i++)
    {
        printf("%c", array[i]); /* Prints out all values declared in the array*/
    }

    return 0;
}

You could also change the declaration of the array to char array[255] , since it only holds characters. For the purposes of printf() it doesn't matter, because char variables are automatically converted to int when calling a variadic function like printf (but I wouldn't be surprised if compilers print a warning about it, since it's unusual).

Answer 2

Your initial code is already pretty accurate.

Your only mistake is: printf("%d", array[i]);

The %d specifier will output an signed decimal integer , to output a character use the %c specifier. You can view all the documentation (including specifiers) for printf here .

I also took the liberty of replacing the elements in the array with integers that result in alphanumeric output.

#include <stdio.h>
#include <conio.h>

int main()
{
    int i;
    int array[255] = { 65, 66, 67 , 68, 69, 70 };

    for(i = 0; i < 6; i++)
    {
        printf("%c", array[i]); // Outputs: ABCDEF
    }

    return 0;
}

Your next steps are to just randomise length and the elements of the array! Good luck.

Answer 3

First of all the computer does not know anything about the characters - from its poit of view everything is just the number.

char type is just the integer value of the size (in bits) CHAR_BITS. In most systems it is 8 bits. Depending on your implementation and compile options char can be signed or unsigned.

Lets consider the signed version. On 32 bit system:

int type is usually 32 bits wide,

short is usually 16 bits wide

char is usually 8 bits wide

so it can be called supershort :)

typedef char supershort;

So there is no difference between them except the range of the values those types can accommodate.

Beginners are often confused by the char constants: 'a' , 'b' .... etc and it makes them think that char is something special , but it is only for the humans convenience - it is much more difficult to remember the whole ASCII table.

You can use them with any other number types: long x = 'a' ; or even double y = '#'

Assuming : you can use char type as any other integer type.