format-specifiers

问题 I want to format a floating point number as follows in C# such that the entire width of the floating point number in C# is a fixed length (python equivalent format specifier 6.2f) I do NOT want it to be padded with 0's on the left but padded with a white space 100.00 90.45 7.23 0.00 what I have tried so far string.Format({0:###.##},100); string.Format({0:###.##},90.45); string.Format({0:###.##},7.23); string.Format({0:###.##},0.00); but the output is incorrect 100 90.45 7.23 //nothing is

问题 I'm trying to use fscanf to read in data, and part of the input is a float followed by the letter 'e' , for example, 41.72elapsed . When writing the strng for fscanf , I attempted to use "%felapsed" , but this doesn't work, as %fe is its own format specifier. How would I read this in using fscanf ? edit: Here is the code: #include <stdio.h> #include <string.h> #include <stdlib.h> #define CHAR_MAX 1024 int main(int argc, char **argv) { FILE *file_in = fopen(argv[1], "r+"); char out_name[CHAR

问题 I'm trying to use fscanf to read in data, and part of the input is a float followed by the letter 'e' , for example, 41.72elapsed . When writing the strng for fscanf , I attempted to use "%felapsed" , but this doesn't work, as %fe is its own format specifier. How would I read this in using fscanf ? edit: Here is the code: #include <stdio.h> #include <string.h> #include <stdlib.h> #define CHAR_MAX 1024 int main(int argc, char **argv) { FILE *file_in = fopen(argv[1], "r+"); char out_name[CHAR

问题 I'm new to to C language and I'm studying it on a book by Kim N. King. It say that the scanf() looks for number pattern ignoring the whitespaces but I think it also skips on Enter key. While if it looks for characters it obviously takes the whitespace also. Therefore in this example code I have to use getchar() to clear the stream before the second scanf() , otherwise the second one would be executed without waiting for user's input. printf("Enter a char: "); scanf("%c", &ch1); getchar();

来源： https://stackoverflow.com/questions/35347178/unable-to-retrieve-regex-match-results-mfc-c

来源： https://stackoverflow.com/questions/9953125/specifying-maximum-printf-field-width-for-numbers-truncating-if-necessary

问题 Initially I declared variables x and y as type int: #include<stdio.h> int main(){ int x, y = 0 ; x = 1 / y; printf("%d", x); return 0; } Program crashed (for obvious reasons). Now I declared variables x and y as double: #include<stdio.h> int main(){ double x, y = 0 ; x = 1 / y; printf("%d", x); return 0; } But Output: 0. (why?) Then I changed %d to %f in printf: #include<stdio.h> int main(){ double x, y = 0 ; x = 1 / y; printf("%f", x); return 0; } Output: 1.#INF00 I don't understand what is

问题 Initially I declared variables x and y as type int: #include<stdio.h> int main(){ int x, y = 0 ; x = 1 / y; printf("%d", x); return 0; } Program crashed (for obvious reasons). Now I declared variables x and y as double: #include<stdio.h> int main(){ double x, y = 0 ; x = 1 / y; printf("%d", x); return 0; } But Output: 0. (why?) Then I changed %d to %f in printf: #include<stdio.h> int main(){ double x, y = 0 ; x = 1 / y; printf("%f", x); return 0; } Output: 1.#INF00 I don't understand what is

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 want to do something like this: NSLog(@"You got: %x", booleanValue); where x is the specifier. But I can't find one! I want to avoid: if (booleanValue) { NSLog(@"You got: YES"); } else { NSLog(@"You got: NO"); } Any ideas? The docs didn't have a Boolean specifier. %@ didn't work either. 回答1: Here are two things that work: NSLog(@"You got: %@",booleanValue ? @"YES" : @"NO"); or you can cast: NSLog(@"You got: %d", (int)booleanValue); Which will output 0 or 1 回答2: You can cast it to an int and