Recent questions tagged C

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c - Count each bit-position separately over many 64-bit bitmasks, with AVX but not AVX2

(Related: How to quickly count bits into separate bins in a series of ints on Sandy Bridge? is an earlier duplicate ... 0; } Thanks in advance! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - MinGW GCC: "Unknown conversion type character 'h'" (snprintf)

Okay, I've run into a strange issue compiling a C file with MinGW (GCC 4.6.2) on Windows 7. The ... print char variables as hexadecimal values.) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Passing too many arguments to printf

Any C programmer who's been working for more than a week has encountered crashes that result from calling printf ... inducing pitfall here, too? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to printf long long

I'm doing a program that aproximate PI and i'm trying to use long long, but it isn't working. Here is the code ... printf("%lld ",4*pi); } } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Interprocess mutex with pthreads

I want to use a mutex which will be used to synchronize access to some variables residing in the memory ... that will be very appreciated. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Passing parameters dynamically to variadic functions

I was wondering if there was any way to pass parameters dynamically to variadic functions. i.e. If I have a ... there is no other option? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Keyboard IRQ within an x86 kernel

I'm trying to program a very simple kernel for learning purposes. After reading a bunch of articles about ... this problem? Any suggestions? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why getch() returns before press any key?

int main(int argc, char *argv[], char *env[]) { printf("Press any key to exit. "); getch(); return 0; } ... press Enter, it's not what I want. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Bitwise rotate left function

I am trying to implement a rotate left function that rotates an integer x left by n bits Ex: rotateLeft(0x87654321,4) ... 0xf]. Should be 1[0x1] See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - for loop missing initialization

I've seen for(;;) and for ( ; *s != ''; s++) Why is it blank like that. Thanks. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Using Dynamic Memory allocation for arrays

How am I supposed to use dynamic memory allocations for arrays? For example here is the following array in which i ... help me in this regard. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Print all permutation in lexicographic order

I want to print all permutation of string in lexicographic order. I wrote this code: void permute(char *a, int i, int ... (I'm a beginner in C). See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the easiest way to count the newlines in an ASCII file?

Which is the fastest way to get the lines of an ASCII file? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How can I get a filename from a file descriptor inside a kernel module?

I need to get the name of a file from a given file descriptor, inside a small linux kernel module that I wrote. ... solution). How can I do it? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Strange array initialize expression?

What is the meaning of following Code? Code is from the regression test suite of GCC. static char * name[] = { [0x80000000] = "bar" }; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - .bss vs COMMON: what goes where?

From my book: .bss: Uninitialized global C variables COMMON: Uninitalized data objects that are not yet allocated I ... in .bss... confused See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why is strdup considered to be evil

I've seen some posters stating that strdup is evil. Is there a consensus on this? I've used it without any guilty ... have been @R..'s answer. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Count number of digits after `.` in floating point numbers?

This is one interview question. How do you compute the number of digit after . in floating point number. e.g ... 7 bits indicate the mantissa. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is it with printf() sending output to buffer?

I am going through "C PRIMER PLUS" and there is this topic about "OUTPUT FLUSHING". Now it says: printf() ... It still outputs on the console. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Swap nodes in a singly-linked list

I am trying to swap two nodes. For example if the nodes are a and b I am passing the pointers (a-1)-> ... it's an infinite loop. Please help. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Get scanf to quit when it reads a newline?

If I input 5 5 at the terminal, press enter, and press enter again, I want to exit out of the loop. int ... to quit after reading an empty line? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the proper way of implementing a good "itoa()" function?

I was wondering if my implementation of an "itoa" function is correct. Maybe you can help me getting it a bit more " ... char *argv[]) { ... See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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239 views

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c - How is the array stored in memory?

I have a simple program which initializes an array as: int a[]={10,20,30,40,50}; char *p; p=(char*)a; ... it stored on the stack or the heap? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Cannot calculate factorials bigger than 20! ! How to do so?

I am using unsigned long long integer format in order to calculate big factorials. However my code fails at some point can you ... < p; k++); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - multiple word string input through scanf( )

what was the syntax to input strings with more than one word i.e with space in between through scanf() not gets() See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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323 views

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c - multi-word addition using the carry flag

GCC has 128-bit integers. Using these I can get the compiler to use the mul (or imul with only one operand ... s more complicated than I expect. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Do I get a performance penalty when mixing SSE integer/float SIMD instructions

I've used x86 SIMD instructions (SSE1234) in the form of intrinsics quite a lot lately. What I found ... algorithms applied to each instruction. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to trap unaligned memory access?

I am working on a pet open-source project that implements some stream cipher algorithms and I am having trouble with ... running Linux 2.6.32. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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