1.linux自实现printf

#include 
#include    /* 使用va_list、va_start等必须包含的头文件 */
#include 
#include 

/* linux C没有itoa函数,所以要自己写 */
char *itoa(int i, char *str)
{
    int mod, div = fabs(i), index = 0;
    char *start, *end, temp;

    do
    {
        mod = div % 10;
        str[index++] = '0' + mod;
        div = div / 10;
    }while(div != 0);

    if (i < 0)
        str[index++] = '-';

    str[index] = '\0';

    for (start = str, end = str + strlen(str) - 1;
        start < end; start++, end--)
    {
        temp    = *start;
        *start    = *end;
        *end    = temp;
    }
    
    return str;
}

void print(const char *fmt, ...)
{
    char str[100];
    unsigned int len, i, index;
    int iTemp;
    char *strTemp;
    va_list args;

    va_start(args, fmt);
    len = strlen(fmt);
    for (i=0, index=0; i