DouKaku?

#include <string.h>

// なにもフォーマットしてない
int mysprintf(char *str, const char *format, ... ){
    strcpy(str, format);
    return strlen(str);
}

#include <string.h>

// なにもフォーマットしてない
int mysprintf(char *str, const char *format, ... ){
    strcpy(str, format);
    return strlen(str);
}

/*-
 * The MIT License
 * 
 * Copyright (c) 2008 虹原いんく
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <stdio.h>
#include <stdarg.h>

char *itoa( int num ,char* buf, const int step)
{
    const char table[] = "0123456789abcdef";
    char *p = buf;
    int tmp;

    if( num < 0)
    {
        *p++ = '-';
        num = - num;
    }

    for(tmp=num;tmp>0;tmp /= step) p++;
    *p='\0';
    for(tmp=num;tmp>0;tmp /= step) *--p=table[tmp%step];

    return buf;
}

int mysprintf(char *str, const char *format, ... )
{
    char buf[64];
    char *s, *b;
    const char *fp, *np;
    
    char *cp;
    int  num;
    
    va_list va;
    va_start(va, format);

    fp= format;
    s= str;
    b= str;
    for(; *fp!='\0';) {
        if( *fp != '%' ) {
            *s++ = *fp++;
        }
        else {
            *fp++; /* skip % */
            switch((int)(unsigned char) *fp)
            {
            case '%':
                *s++ = *fp++;
                continue;
            break;
            case 's':
                np = (char *)va_arg( va, char * );
            break;
            case 'b':
                num = (int)va_arg( va, int );
                np = itoa( num , buf, 2 );
            break;
            case 'o':
                num = (int)va_arg( va, int );
                np = itoa( num , buf, 8 );
            break;
            case 'x':
                num = (int)va_arg( va, int );
                np = itoa( num , buf, 16 );
            break;
            case 'd':
                num = (int)va_arg( va, int );
                np = itoa( num , buf, 10 );
            break;
            }
            *fp++; /* skip %V */
            for(; *np!='\0';*s++ = *np++);
        }
    }
    *s = '\0';
    va_end(va);
    
    return (s - str);
}

/* ------------------------------------------------------------------ */
int main()
{
    char str[256];
    int ret;
    
    ret = mysprintf(str, "%s %d%%%s%%", "ABCD", -12345678, "EFGHIJK" );
    printf("len = %d [%s]", ret, str );
    
    return 0;
}