#include <stdio.h>
char *itoa(int value, char *string, int radix)
{
    int rt=0;
    if(string==NULL)
        return NULL;
    if(radix<=0 || radix>30)
        return NULL;
    rt = snprintf(string, radix, "%d", value);
    if(rt>radix)
        return NULL;
    string[rt]='\0';
    return string;
}

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