Displaying ASCII value of a character in c [duplicate]

This question already has answers here: Printing chars and their ASCII-code in C (8 answers) Closed 5 years 开发者_运维百科ago.

I have accepted a character as an input from the user. I want to print the ASCII value of that character as an output. How can I do that without using any pre-defined function (if it exists) for the same?

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Instead of printf("%c", my_char), use %d to print the numeric (ASCII) value.

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Also consider printf("%hhu", c); to precisely specify conversion to unsigned char and printing of its decimal value.

Update0

So I've actually tested this on my C compiler to see what's going on, the results are interesting:

char c = '\xff';
printf("%c\n", c);
printf("%u\n", c);
printf("%d\n", c);
printf("%hhu\n", c);

This is what is printed:

� (printed as ASCII)
4294967295 (sign extended to unsigned int)
-1 (sign extended to int)
255 (handled correctly)

Thanks caf for pointing out that the types may be promoted in unexpected ways (which they evidently are for the %d and %u cases). Furthermore it appears the %hhu case is casting back to a char unsigned, probably trimming the sign extensions off.

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This demo shows the basic idea:

#include <stdio.h>

int main()
{
    char a = 0;
    scanf("%c",&a);

    printf("\nASCII of %c is %i\n", a, a); 

    return 0;
}

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The code printf("%c = %d\n", n, n); displays the character and its ASCII.

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This will generate a list of all ASCII characters and print it's numerical value.

#include <stdio.h>
#define N 127

int main()
{
    int n;
    int c;

    for (n=32; n<=N; n++) {
        printf("%c = %d\n", n, n);
    }

    return 0;
} 

---

 #include "stdio.h"
 #include "conio.h"
 //this R.M.VIVEK coding for no.of ascii values display and particular are print

void main()
{
    int rmv,vivek;
    clrscr();

    for(rmv=0;rmv<=256;rmv++)
    {
        if(printf("%d = %c",rmv,rmv))
    }

    printf("Do you like particular ascii value\n enter the 0 to 256 number");
    scanf("%d",&vivek);
    printf("\nthe rm vivek ascii value is=%d",vivek);
    getch();
}