来自:https://www.cnblogs.com/02xiaoma/archive/2012/06/22/2558618.html
#include <stdio.h> #include <stdarg.h>
#include "print.h"
int main(void)
{
print("print: %c
", 'c');
print("print %d
", 1234567);
print("print: %f
", 1234567.1234567);
print("print: %s
", "string test");
print("print: %b
", 0x12345ff);
print("print: %x
", 0xabcdef);
print("print: %%
");
return 0;
}
void print(char* fmt, ...)
{
double vargflt = 0;
int vargint = 0;
char* vargpch = NULL;
char vargch = 0;
char* pfmt = NULL;
va_list vp;
va_start(vp, fmt);
pfmt = fmt;
while(*pfmt)
{
if(*pfmt == '%')
{
switch(*(++pfmt))
{
case 'c':
vargch = va_arg(vp, int);
/* va_arg(ap, type), if type is narrow type (char, short, float) an error is given in strict ANSI
mode, or a warning otherwise.In non-strict ANSI mode, 'type' is allowed to be any expression. */
printch(vargch);
break;
case 'd':
case 'i':
vargint = va_arg(vp, int);
printdec(vargint);
break;
case 'f':
vargflt = va_arg(vp, double);
/* va_arg(ap, type), if type is narrow type (char, short, float) an error is given in strict ANSI
mode, or a warning otherwise.In non-strict ANSI mode, 'type' is allowed to be any expression. */
printflt(vargflt);
break;
case 's':
vargpch = va_arg(vp, char*);
printstr(vargpch);
break;
case 'b':
case 'B':
vargint = va_arg(vp, int);
printbin(vargint);
break;
case 'x':
case 'X':
vargint = va_arg(vp, int);
printhex(vargint);
break;
case '%':
printch('%');
break;
default:
break;
}
pfmt++;
}
else
{
printch(*pfmt++);
}
}
va_end(vp);
}
void printch(char ch)
{
console_print(ch);
}
void printdec(int dec)
{
if(dec==0)
{
return;
}
printdec(dec/10);
{
printch( (char)(dec%10 + '0'));
}
void printflt(double flt)
{
int icnt = 0;
int tmpint = 0;
tmpint = (int)flt;
printdec(tmpint);
printch('.');
flt = flt - tmpint;
tmpint = (int)(flt * 1000000);
printdec(tmpint);
}
void printstr(char* str)
{
while(*str)
{
printch(*str++);
}
}
void printbin(int bin)
{
if(bin == 0)
{
printstr("0b");
return;
}
printbin(bin/2);
printch( (char)(bin%2 + '0'));
}
void printhex(int hex)
{
if(hex==0)
{
printstr("0x");
return;
}
printhex(hex/16);
if(hex < 10)
{
printch((char)(hex%16 + '0'));
}
else
{
printch((char)(hex%16 - 10 + 'a' ));
}
}