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c:stdio.h:fprintf

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c:stdio.h:fprintf [2013/01/22 22:02] (current)
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 +{{keywords>wiki library source code example reference}}
 +====== fprintf ======
  
 +<code c>
 +     int fprintf(FILE *stream, const char *format, ...);
 +</code>
 +
 +Converts (according to format format) and writes output to stream stream. Number of characters written, or negative value on error, is returned.\\
 +\\
 +optional flag:\\
 +\\
 +-  left adjust\\
 ++  always sign\\
 +0  zero pad\\
 +#  Alternate form: for conversion character o, first digit will be zero, for [xX], prefix 0x or 0X to non-zero value, for [eEfgG], always decimal point, for [gG] trailing zeros not removed. \\
 +\\
 +optional minimum width: if specified as *, value taken from next argument (which must be int).\\
 +optional . (separating width from precision)\\
 +optional precision: for conversion character s, maximum characters to be printed from the string, for [eEf], digits after decimal point, for [gG], significant digits, for an integer, minimum number of digits to be printed. If specified as *, value taken from next argument (which must be int).\\
 +\\
 +optional length modifier:\\
 +
 +h  short or unsigned short\\
 +l  long or unsigned long\\
 +L  long double\\
 +
 +conversion character:\\
 +
 +d,i   int argument, printed in signed decimal notation\\
 +o     int argument, printed in unsigned octal notation\\
 +x,X   int argument, printed in unsigned hexadecimal notation\\
 +u     int argument, printed in unsigned decimal notation\\
 +c     int argument, printed as single character\\
 +s     char* argument\\
 +f     double argument, printed with format [-]mmm.ddd\\
 +e,E   double argument, printed with format [-]m.dddddd(e|E)(+|-)xx\\
 +g,G   double argument\\
 +p     void* argument, printed as pointer\\
 +n     int* argument : the number of characters written to this point is written into argument\\
 +%     no argument; prints %\\
 +
 +
 +
 +===== C Sourcecode Example =====
 +<code c>
 +/* 
 + * fprintf example code
 + * http://code-reference.com/c/stdio.h/fprintf 
 + */
 +
 +
 +#include <stdio.h> /* including standard library */
 +//#include <windows.h> /* uncomment this for Windows */
 +
 +#define MAX 60
 +
 +int main ( void )
 +{
 +   FILE * stream;
 +   char string[MAX];
 +   char c;
 +
 +   sprintf(string,"This string will be cut here - This will not be shown");
 +
 +   stream = fopen ("test.txt","w");
 +   fprintf (stream, "%-8.28s ",string); // -8 is minimun and after the . (in this case 28) is maximum chars
 +   
 +   freopen("test.txt", "r", stream);
 +   while((c = fgetc(stream) ) != EOF) {
 +      printf("%c", c );
 +      }
 +   
 +   printf("\n");
 +   fclose (stream);
 +   return 0;
 +}
 +
 +</code>
 +
 +==== fprintf output example ====
 +    output:./fprintf 
 +    This string will be cut here 
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c/stdio.h/fprintf.txt · Last modified: 2013/01/22 22:02 (external edit)

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