Questions tagged as 'c'


What does "??! ??!" mean in C language?

I once saw a code in C with the following line: ... if (condicao1 ??!??! condicao2){ /* faca algo */ } ... What does "??! ??!" mean? in C language?     
asked by 04.02.2014 / 12:20

How to make case-insensitive comparisons in SQLite?

As there is an obsession with questions with accents, here's mine:) SQLite allows you to make direct comparisons or through like with any encoding / charset from byte to . It only allows comparisons to be made regardless of case...
asked by 09.01.2014 / 14:01

Arduino I2C sends unexpected NACK

I am using a development board of microchip (explorer 16) with pic24f128ga010 as Master and Arduino as Slave . The PIC is sending everything right, but for some reason arduino sends NACK to all date , only sends ACK...
asked by 29.03.2015 / 18:43

Mathematical division needs

On the Windows calculator: 9 / 3,0001 = 2,999 ... In my program: 9 / 3,0001 = 3; I would like to get this level of precision using C. See excerpts from my program: double op(double num1, double num2, char c) { if(c == '/')...
asked by 25.10.2014 / 18:23

Can a C compiler generate a 64-bit executable where pointers are 32-bits?

Most programs fit well in address space of less than 4GB, but in some cases the program may need to use the new processor features / instructions that are only available in the x64 architecture. Unfortunately the normal procedure would be to gene...
asked by 15.01.2014 / 02:37

Why use while (0)?

In the Linux code I saw some macros with: do { }while(0) Is there a reason? Because apparently there is no logic to a loop of repetition where the code repeats only once.     
asked by 13.08.2015 / 21:13

What is the purpose of void in C?

I have questions about using void in functions. 1 ° Example: int somaV(int valor_1, int valor_2) { return valor_1 + valor_2; } I know that this function will return an integer which is the sum of the two parameters in the func...
asked by 09.11.2015 / 15:54

Programming in C for ARM

I will start a project in C that will have as a% of a board Colibri T20 processor with NVIDIA Tegra 2 ARM , running a lightweight version of Linux. I would like to know if, in addition to having to use a processor-compatible cross compiler...
asked by 20.12.2013 / 18:54

Receive an expression and compute in C

I'm developing this program that should receive an expression from the user and do the calculation. Ex:    Enter an expression       3 * 5-1       14 My problem is how to handle the expression sent by the user. It was recommended to...
asked by 18.02.2014 / 20:22

How can -1 be greater than 4?

How can this code run this way ? #include <stdio.h> int main(void) { printf("tamanho de um inteiro: %d\n", sizeof(int)); if(sizeof(int) > -1) { printf("4 é maior que -1"); } else { printf("-1 é maior que...
asked by 21.01.2015 / 13:40