How to convert from ASCII to Hex and vice versa? [closed]

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I need to convert ASCII to HEX and HEX to A开发者_高级运维SCII by using a C program.

How can I do that?

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Here's a simplistic function to convert one character to a hexadecimal string.

char hexDigit(unsigned n)
{
    if (n < 10) {
        return n + '0';
    } else {
        return (n - 10) + 'A';
    }
}

void charToHex(char c, char hex[3])
{
    hex[0] = hexDigit(c / 0x10);
    hex[1] = hexDigit(c % 0x10);
    hex[2] = '\0';
}

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Its pretty easy. Scan through character by character ... best to start from the end. If the character is a number between 0 and 9 or a letter between a and f then place it in the correct position by left shifting it by the number of digits you've found so far.

For converting to a string then you do similar but first you mask and right shift the values. You then convert them to the character and place them in the string.