Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Double to const char conversion
Top Forums Programming Double to const char conversion Post 302770120 by DGPickett on Thursday 14th of February 2013 01:19:50 PM
Old 02-14-2013
PS: I prefer a no-*printf() solution on inner loops for speed, and just memcpy() the bytes of "0.0000*" I need to the buffer, or often even better, fwrite() or write() first the "0.0000*" bytes out and then the fps, so there is no excess copying. The idea of parsing the "%.*s%s" over and over bothers me. Maybe the optimizers chew it up? Output is, after all, the point of the exercise. Work back from output to the minimum variables you need. Write stuff in pieces if pieces is how it comes. However, write() is a system call where you can lose the CPU, so the FILE* buffering of fwrite() is a good thing for little pieces. And putc() is a macro, so it is always inline optimizable.
Last edited by DGPickett; 02-14-2013 at 02:24 PM..
 

10 More Discussions You Might Find Interesting

1. Programming

char to int64 conversion

Hi, I'm converting a C program that I made using the Visual Studio. I now use GCC (over Linux) and can't find some equivalences. I changed my __int64 definitions to unsigned long long, but can't find an equivalent to the microsoft i64toa() function, which let you convert a char* to a 64 bit... (1 Reply)
Discussion started by: Raspoutine
1 Replies

2. Programming

diff b/w char const in C/C++

hi, what is the difference b/w char in C and C++.and give me the examples. Thanks... sarwan (3 Replies)
Discussion started by: sarwan
3 Replies

3. UNIX for Dummies Questions & Answers

int open(const char *pathname, int flags, mode_t mode) doubt...

hello everybody! I want to create a file with permissions for read, write, and execute to everybody using C, so I write this code: #include <stdio.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> int main(){ int fileDescriptor; fileDescriptor =... (2 Replies)
Discussion started by: csnmgeek
2 Replies

4. UNIX for Dummies Questions & Answers

ANSI C, char to hex conversion

Hi, I have a char buf,ch; and the buf is filled with the result from MySQL server which I get like this numbytes = recv(sock, buf, 1024, 0));I have the followingcode to display the results printf("received %ld bytes:\n",numbytes); for(c=0;c<numbytes;c++){ ch = (char)buf; ... (2 Replies)
Discussion started by: alikims
2 Replies

5. Programming

concat const char * with char *

hello everybody! i have aproblem! i dont know how to concatenate const char* with char const char *buffer; char *b; sprintf(b,"result.txt"); strcat(buffer,b); thanx in advance (4 Replies)
Discussion started by: nicos
4 Replies

6. Programming

conversion to 'char' from 'int' warning

Hi, I wrote a simple code in C++ converting from UpperToLower case characters. However, my compiler gives me a warning: "warning: conversion to 'char' from 'int' may alter its value". Any tips? I would like to stress, I don't want to load my string into char array. int ToLower(string... (4 Replies)
Discussion started by: kajolo
4 Replies

7. Programming

error: invalid conversion from ‘const char*’ to ‘char*’

Compiling xpp (The X Printing Panel) on SL6 (RHEL6 essentially): xpp.cxx: In constructor ‘printFiles::printFiles(int, char**, int&)’: xpp.cxx:200: error: invalid conversion from ‘const char*’ to ‘char*’ The same error with all c++ constructors - gcc 4.4.4. If anyone can throw any light on... (8 Replies)
Discussion started by: GSO
8 Replies

8. Programming

Using const char*

I am writing some code in C++ to print a message using fprintf Here is an example void pr_desc( FILE* stream, int shift, const char* desc) { const char* format="%*s\e; fprintf(stream,format,shift,"",desc); } I call it using const char* desc; ... (4 Replies)
Discussion started by: kristinu
4 Replies

9. Programming

Invalid conversion from char* to char

Pointers are seeming to get the best of me and I get that error in my program. Here is the code #include <stdio.h> #include <stdlib.h> #include <string.h> #define REPORTHEADING1 " Employee Pay Hours Gross Tax Net\n" #define REPORTHEADING2 " Name ... (1 Reply)
Discussion started by: Plum
1 Replies

10. Programming

Bool vs char * conversion

I have a problem at make step to install a downloaded package consisted of different programs. In file included from kcdbext.cc:16:0: kcdbext.h: In member function �char* kyotocabinet::IndexDB::get(const char*, size_t, size_t*)’: kcdbext.h:1281:14: error: cannot convert �bool’ to... (3 Replies)
Discussion started by: yifangt
3 Replies

LEARN ABOUT BSD

fread

FREAD(3S)																 FREAD(3S)

NAME

       fread, fwrite - buffered binary input/output

SYNOPSIS

       #include <stdio.h>

       fread(ptr, sizeof(*ptr), nitems, stream)
       FILE *stream;

       fwrite(ptr, sizeof(*ptr), nitems, stream)
       FILE *stream;

DESCRIPTION

       Fread reads, into a block beginning at ptr, nitems of data of the type of *ptr from the named input stream.  It returns the number of items
       actually read.

       If stream is stdin and the standard output is line buffered, then any partial output line will be flushed before any  call  to  read(2)	to
       satisfy the fread.

       Fwrite  appends	at  most  nitems  of data of the type of *ptr beginning at ptr to the named output stream.  It returns the number of items
       actually written.

SEE ALSO

       read(2), write(2), fopen(3S), getc(3S), putc(3S), gets(3S), puts(3S), printf(3S), scanf(3S)

DIAGNOSTICS

       Fread and fwrite return 0 upon end of file or error.

4th Berkeley Distribution					   May 15, 1985 							 FREAD(3S)
All times are GMT -4. The time now is 07:19 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy