int_to_string.c File Reference

Convert a positive integer to string (non-standard function) representation. More...

#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

Include dependency graph for int_to_string.c:

Functions
char *	int_to_string (uint16_t value, char *dest, int base)
	Converts an integer value to a null-terminated string using the specified base and stores the result in the array given by str parameter. More...
static void	test ()
	Test function. More...
int	main ()
	Driver Code.

Detailed Description

Convert a positive integer to string (non-standard function) representation.

Function Documentation

int_to_string()

char* int_to_string	(	uint16_t	value,
		char *	dest,
		int	base
	)

Converts an integer value to a null-terminated string using the specified base and stores the result in the array given by str parameter.

Parameters

value	Value to be converted to a string.
dest	pointer to array in memory to store the resulting null-terminated string.
base	Numerical base used to represent the value as a string, between 2 and 16, where 10 means decimal base, 16 hexadecimal, 8 octal, and 2 binary.

Returns

A pointer to the resulting null-terminated string, same as parameter str.

Note

The destination array must be pre-allocated by the calling function.

{
    const char hex_table[] = {'0', '1', '2', '3', '4', '5', '6', '7',
                              '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
 
    int len = 0;
    do
    {
        dest[len++] = hex_table[value % base];
        value /= base;
    } while (value != 0);
 
    /* reverse characters */
    for (int i = 0, limit = len / 2; i < limit; ++i)
    {
        char t = dest[i];
        dest[i] = dest[len - 1 - i];
        dest[len - 1 - i] = t;
    }
    dest[len] = '\0';
    return dest;
}

test()

static void test ( void  )

static

Test function.

Returns

void

{
    const int MAX_SIZE = 100;
    char *str1 = (char *)calloc(sizeof(char), MAX_SIZE);
    char *str2 = (char *)calloc(sizeof(char), MAX_SIZE);
 
    for (int i = 1; i <= 100; ++i) /* test 100 random numbers */
    {
        /* Generate value from 0 to 100 */
        int value = rand() % 100;
 
        // assert(strcmp(itoa(value, str1, 2), int_to_string(value, str2, 2)) ==
        //        0);
        snprintf(str1, MAX_SIZE, "%o", value);  //* standard C - to octal */
        assert(strcmp(str1, int_to_string(value, str2, 8)) == 0);
        snprintf(str1, MAX_SIZE, "%d", value); /* standard C - to decimal */
        assert(strcmp(str1, int_to_string(value, str2, 10)) == 0);
        snprintf(str1, MAX_SIZE, "%x", value); /* standard C - to hexadecimal */
        assert(strcmp(str1, int_to_string(value, str2, 16)) == 0);
    }
 
    free(str1);
    free(str2);
}

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