getchar

Determining EOF expression

由 馋奶兔 提交于 2019-12-12 05:28:54
问题 I need to verify that the expression getchar() ! = EOF is 0 or 1 . My current code: #include <stdio.h> int main (int argc, char *argv[]) { int c; while (( c= getchar()) != EOF) { printf("%d ", c != EOF); putchar(c); } printf("\n%d\n", c != EOF); } When I try to run that I get 98980980 1 91 81 91 81 01 91 81 01 I`m not sure if I got this right. EDIT: Ok the question was actually " How to generate EOF " and the solution was to press ctrl+D. 回答1: I'm not very sure if you want this answer, but as

Issues with standard input in C

由 自古美人都是妖i 提交于 2019-12-12 04:56:56
问题 I'm making a simple program in C that reads an input. It then displays the number of characters used. What I tried first: #include <stdio.h> int main(int argc, char** argv) { int currentChar; int charCount = 0; while((currentChar = getchar()) != EOF) { charCount++; } printf("Display char count? [y/n]"); int response = getchar(); if(response == 'y' || response == 'Y') printf("Count: %d\n",charCount); } What happened: I would enter some lines and end it with ^D (I'm on Mac). The program would

getch()和getchar()的区别

由 ⅰ亾dé卋堺 提交于 2019-12-12 03:31:44
getch()用于暂停 getchar()用于清理字符型垃圾 getchar()的头文件是<stdio.h> getch()的头文件是<conion.h> getchar() getchar有一个int型的返回值.当程序调用getchar时.程序就等着用户按键.用户输入的字符被存放在键盘缓冲区(输入缓冲区)中.直到用户按回车为止(回车字符也放在缓冲区中).getchar函数的返回值是用户输入的第一个字符的ASCII码,如出错返回-1,且将用户输入的字符回显到屏幕.如用户在按回车之前输入了不止一个字符,其他字符会保留在键盘缓存区中,等待后续getchar调用读取.也就是说,后续的getchar调用不会等待用户按键,而直接读取缓冲区中的字符,直到缓冲区中的字符读完为后,才等待用户按键. getch() getch与getchar基本功能相同,差别是getch直接从键盘获取键值（没有输入缓冲区）,不等待用户按回车,只要用户按一个键,getch就立刻返回,getch返回值是用户输入的ASCII码,出错返回-1.输入的字符不会回显在屏幕上.getch函数常用于程序调试中,在调试时,在关键位置显示有关的结果以待查看,然后用getch函数暂停程序运行,当按任意键后程序继续运行. 主要作用 getch()是读取按键值常放在程序末尾起暂停作用 getchar()是从标准输入设备读取下一个字符 来源：

getchar() only calling every other time

由 旧时模样 提交于 2019-12-12 02:55:06
问题 While using Ch Standard Interpreter, getchar() only runs every other line. C:/> char a = getchar(); C:/> char b = getchar(); b C:/> char c = getchar(); C:/> char d = getchar(); d I have the same issue when using scanf("%c", &a) instead; in Vim the statement is skipped. printf("\nType of Something\nA for SomethingA\nB for SomethingB " "\nC for SomethingC\n\nSelect (A,B,C) > "); char letter = getchar(); // This statement gets skipped return 0; 回答1: When you type "A" on the keyboard, you first

getchar() is giving output in C

由 巧了我就是萌 提交于 2019-12-12 01:53:01
问题 What should this program do, #include<stdio.h> main() { getchar(); } I expect it to show a blank screen until I hit any character on the keyboard. But what it does is quite weird. It displays whatever I press. It never terminates until I press Enter. As far as I know, getchar() should just read one character. It should not output anything. Why is it printing every character that I input? Edit: Why doesn't getchar() stop after reading one character, e.g. in this code: #include <stdio.h> main()

Why is my getchar() not working here?

由 陌路散爱 提交于 2019-12-11 13:31:50
问题 In my program I'm just calculating the costs of things. However, at the end I want a little break at the program asking for the user to just press the Enter button. I supposed getchar() would work here but it doesn't even stop, it just continues to keep printing. I even tried to put a space after the scant formats like scanf("%s "). So two things how do I stop the program to ask for input at getchar() and how do I make it recognize just a enter button. #include <stdio.h> #include <stdlib.h>

confused about getchar and scanf

由 僤鯓⒐⒋嵵緔 提交于 2019-12-11 12:11:23
问题 I'm really confused about the usage of getchar() and scanf() . What's the difference between these two? I know that scanf() [and family] get a character by character from the user [or file] and save it into a variable, but does it do that immediately or after pressing something ( Enter )? and I don't really understand this code, I saw many pieces of code using getchar() and they all let you type whatever you want on the screen and no response happen, but when you press enter it quits. int j,

Why getchar() behaves differently?

由 随声附和 提交于 2019-12-11 12:06:21
问题 I found getchar() is behaving differently in some situations. In the following code, it devours the newline character in the input. #include <stdio.h> // copy input to output; 1st version int main() { int c; while((c = getchar()) != EOF) { putchar(c); } } The input and output in the terminal looks like this. j j b b asdf asdf ashdfn ashdfn It exactly duplicates the input and ignores the newline character in the input due to return key I pressed after each input. However, if there is a printf(

Word count program - stdin

由 怎甘沉沦 提交于 2019-12-11 06:35:48
问题 For below question, Write a program to read English text to end-of-data (type control-D to indicate end of data at a terminal, see below for detecting it), and print a count of word lengths, i.e. the total number of words of length 1 which occurred, the number of length 2, and so on. Define a word to be a sequence of alphabetic characters. You should allow for word lengths up to 25 letters. Typical output should be like this: length 1 : 10 occurrences length 2 : 19 occurrences length 3 : 127

echoing of getchar and '\n' char from stdin

由 纵饮孤独 提交于 2019-12-11 05:09:29
问题 I have already looked at this similar question but i am still wondering if there is another way to stop 1) the terminal echoing with portabilty as this is an assignment and I have already had one java program crash and burn on my teachers computer 2) in my program i search for a '\n' char then if it isn't the first char use getchar then putchar till the next '\n' char which works fine when using redirected stdin but when I try using the program without redirection the enter key is always
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