printf

问题 C++20 introduces std::format . What are the advantages over printf or std::cout . How can I use it and someone give an example of it? 回答1: What are the advantages over printf Type safety. For printf, the programmer must carefully match the format specifier to the type of the argument. If they make a mistake, the behaviour of the program is undefined. This is a very common source of bugs, especially for beginners. To be fair, decent compilers diagnose these mistakes as long as a constant

问题 Edit: What about if we had this char value_arr[8]; // value_arr is set to some value snprintf(value_arr, 8, "%d", *value_arr); is this behavior defined? Let's say for some ungainly reason I have char value_arr[8]; // value_arr is set to some value int* value_i = reinterpret_cast<int*>(value_arr); snprintf(value_arr, 8, "%d", *value_i); // the behaviour in question Is there a guarantee that, for example, if *value_i = 7, then value_arr will take on the value of "7". Is this behavior defined?

问题 Edit: What about if we had this char value_arr[8]; // value_arr is set to some value snprintf(value_arr, 8, "%d", *value_arr); is this behavior defined? Let's say for some ungainly reason I have char value_arr[8]; // value_arr is set to some value int* value_i = reinterpret_cast<int*>(value_arr); snprintf(value_arr, 8, "%d", *value_i); // the behaviour in question Is there a guarantee that, for example, if *value_i = 7, then value_arr will take on the value of "7". Is this behavior defined?

问题 This question already has answers here : Using printf in assembly leads to an empty ouput (2 answers) Can ptrace tell if an x86 system call used the 64-bit or 32-bit ABI? (1 answer) What happens if you use the 32-bit int 0x80 Linux ABI in 64-bit code? (1 answer) Closed 7 days ago . I'm trying to write a Python script to test the output of some various code I've written in assembly against an expected output. However I am having difficulty redirecting the output into a file. I have written the

问题 sprintf_s is a Microsoft implementation of the function sprintf where they patched a flaw, adding an argument to take a boundary value where the function is limited to write. An equivalent was introduced in C++11 : snprintf . But here, we are talking of C++03 syntax. Signatures: count_char_written sprintf(char* string_out, const char* output_template, VARIADIC_ARGS); // and count_char_written sprintf_s(char* string_out, size_t buffer_max_size, const char* output_template, VARIADIC_ARGS);

问题 This question already has answers here : What are the rules of automatic stdout buffer flushing in C? (5 answers) Closed 2 months ago . Does the printf() function in C need a \n at the end in order to work ? I tried printing out a simple statement without a newline at the end and it didn't work. Thanks. 回答1: The likely reason is a line buffered stdout , (this is implementation defined so I can't be 100% sure). In these implementations the content written to the buffer won't immediately be

问题 This question already has answers here : What are the rules of automatic stdout buffer flushing in C? (5 answers) Closed 2 months ago . Does the printf() function in C need a \n at the end in order to work ? I tried printing out a simple statement without a newline at the end and it didn't work. Thanks. 回答1: The likely reason is a line buffered stdout , (this is implementation defined so I can't be 100% sure). In these implementations the content written to the buffer won't immediately be

问题 This question already has answers here : What are the rules of automatic stdout buffer flushing in C? (5 answers) Closed 2 months ago . Does the printf() function in C need a \n at the end in order to work ? I tried printing out a simple statement without a newline at the end and it didn't work. Thanks. 回答1: The likely reason is a line buffered stdout , (this is implementation defined so I can't be 100% sure). In these implementations the content written to the buffer won't immediately be

问题 Why the compiler gives me the error "too many arguments for format" when I use the specifier F in CodeBlocks? #include <stdio.h> int main() { float x = 3.14159; printf("%f\n", x); printf("%F\n", x); return 0; } The errors: error: unknown conversion type character 'F' in format [-Werror=format=] error: too many arguments for format [-Werror=format-extra-args] 回答1: Looks like some versions of GCC don't recognize %F , oddly enough. My gcc version 9.2.0 (tdm64-1) for windows with C11 standard,

问题 I need to print contents of multiple arrays in my code. Eg function performOp($n, $inputArr, $workArr) { printf("Entered function, value of n is %d", $n); print_r($inputArr); print_r($workArr); $width =0; } Now, Instead of writing print_r twice, is there any way I can write a single statement and print both the arrays ? Also, If I want to print "Input array value is " before displaying the Array{}, is there a way to do so using printf or any other function? I tried writing printf("Value of