syntax

问题 I got an error of "No instance of overloaded function" when I used resize(). I'm aware that what's inside of resize() might be wrong as well. I'm trying to resize x, an array of floats to all zeros. Not sure if std::vector>(0, 0) would be the right syntax for it as I am very new to C++. How do I solve the existing error? void IDFT(const std::vector<std::complex<float>> &Xf, std::vector<float> &x) { // allocate space for the vector holding the frequency bins // initialize all the values in the

问题 I am a bit confused about array declaration in C. I know that it's possible to do this: int a[20]; // Reserved space for 20 int array int b[] = {32, 431, 10, 42}; // Length in square brackets is auto-calculated int *c = calloc(15, sizeof(int)); // Created a pointer to the dynamic int array But is it possible to do this?: int my_array[sizeof(int) * 5]; Is it a valid code, or an array length should be a constant expression (in ANSI C)? 回答1: sizeof(int) * 5 used in the example statement in your

问题 I am a bit confused about array declaration in C. I know that it's possible to do this: int a[20]; // Reserved space for 20 int array int b[] = {32, 431, 10, 42}; // Length in square brackets is auto-calculated int *c = calloc(15, sizeof(int)); // Created a pointer to the dynamic int array But is it possible to do this?: int my_array[sizeof(int) * 5]; Is it a valid code, or an array length should be a constant expression (in ANSI C)? 回答1: sizeof(int) * 5 used in the example statement in your

问题 What's the difference between packing a frame "in line" versus ='ing it to a variable and .pack'ing it on the next line? So I saw how to do grid and pack at the same time (see here), but after playing around with it, I ran into something weird. If you change line 16/17 from: f5 = Frame(mainF, bg = "yellow", height=100, width = 60) f5.pack(side=BOTTOM,fill=NONE) to: f5 = Frame(mainF, bg = "yellow", height=100, width = 60).pack(side=BOTTOM,fill=NONE) At the end of the code where the buttons get

问题 What's the difference between packing a frame "in line" versus ='ing it to a variable and .pack'ing it on the next line? So I saw how to do grid and pack at the same time (see here), but after playing around with it, I ran into something weird. If you change line 16/17 from: f5 = Frame(mainF, bg = "yellow", height=100, width = 60) f5.pack(side=BOTTOM,fill=NONE) to: f5 = Frame(mainF, bg = "yellow", height=100, width = 60).pack(side=BOTTOM,fill=NONE) At the end of the code where the buttons get

问题 Accidentally I compiled a source similar to this: //void y(); //optionally declaring y() void x() { //some code... void y(); //some code... } //void y() {/*some code*/} //optionally defining y() This was compiled with VS 2017 and also two clang versions. None of these compilers complained about this source code – no errors, no warnings. There was a typo in my code – in this example, there should be no void in front of y() and therefore y() was supposed to be called, so it was a rather sneaky

问题 In AT&T syntax instructions often have to be suffixed with the appropriate operand size, with q for operations on 64-bit operands. However in MMX and SSE there is also movq instruction, with the q being in the original Intel mnemonic and not an additional suffix. So how will this be represented in AT&T? Is another q suffix needed like movqq %mm1, %mm0 movqq %xmm1, %xmm0 or not? And if there are any other instructions that end like AT&T suffixes (like paddd , slld ), do they work the same way?

问题 In AT&T syntax instructions often have to be suffixed with the appropriate operand size, with q for operations on 64-bit operands. However in MMX and SSE there is also movq instruction, with the q being in the original Intel mnemonic and not an additional suffix. So how will this be represented in AT&T? Is another q suffix needed like movqq %mm1, %mm0 movqq %xmm1, %xmm0 or not? And if there are any other instructions that end like AT&T suffixes (like paddd , slld ), do they work the same way?

问题 I just learned switch statements. I was practicing it by building something. When i set the value of variable to a number it works but when i asks the user for a number it always outputs the default statement . It works with this code: confirm("You want to learn basic counting?"); var i = 0; switch (i) { case 0: console.log(i); i++ case 1: console.log(i); i++; case 2: console.log(i); i++; case 3: console.log(i); i++; case 4: console.log(i); i++; case 5: console.log(i); i++; case 6: console

问题 I've been noticing some unexpected results with my import s, and I'm hoping to understand what's really going on. I started with the following: import java.util.*; import java.io.*; import java.nio.*; import java.nio.file.Path; import java.nio.file.StandardOpenOption.*; import java.nio.file.Paths; and then found that ArrayList and ListIterator didn't work...so I added import java.util.ArrayList; import java.util.ListIterator; and everything works perfectly. I would have assumed that java.util