printf, wprintf

Header File

stdio.h

Category

Console I/O Routines

Prototype

int printf(const char *format[, argument, ...]);

int wprintf(const wchar_t *format[, argument, ...]);

Description

Writes formatted output to stdout.

The printf function:

Accepts a series of arguments
Applies to each argument a format specifier contained in the format string *format
Outputs the formatted data (to the screen, a stream, stdout, or a string)

There must be enough arguments for the format. If there are not, the results will be unpredictable and likely disastrous. Excess arguments (more than required by the format) are merely ignored.

Note: For Win32 GUI applications, stdout must be redirected.

Return Value

On success, printf returns the number of bytes output.

On error, printf returns EOF.

More About printf

Example

Copy Code

#include <stdio.h>
#include <string.h>
#define I 555
#define R 5.5
int main(void)
{
   int i,j,k,l;
   char buf[7];
   char *prefix = buf;
   char tp[20];
   printf("prefix  6d      6o      8x        10.2e        "
          "10.2f\n");
   strcpy(prefix,"%");
   for (i = 0; i < 2; i++)
   {
      for (j = 0; j < 2; j++)
         for (k = 0; k < 2; k++)
            for (l = 0; l < 2; l++)
            {
               if (i==0)  strcat(prefix,"-");
               if (j==0)  strcat(prefix,"+");
               if (k==0)  strcat(prefix,"#");
               if (l==0)  strcat(prefix,"0");
               printf("%5s |",prefix);
               strcpy(tp,prefix);
               strcat(tp,"6d |");
               printf(tp,I);
               strcpy(tp,"");
               strcpy(tp,prefix);
               strcat(tp,"6o |");
               printf(tp,I);
               strcpy(tp,"");
               strcpy(tp,prefix);
               strcat(tp,"8x |");
               printf(tp,I);
               strcpy(tp,"");
               strcpy(tp,prefix);
               strcat(tp,"10.2e |");
               printf(tp,R);
               strcpy(tp,prefix);
               strcat(tp,"10.2f |");
               printf(tp,R);
               printf("  \n");
               strcpy(prefix,"%");
            }
       }
   return 0;
}

Portability

	POSIX	Win32	ANSI C	ANSI C++
printf	+	+	+	+
_wprintf		+

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