putchar

How are getchar() and putchar() Macros?

由 丶灬走出姿态 提交于 2019-12-26 09:47:33
问题 From what I understand about macros in C, they are predefined constants that will be used throughout the program with their constant value, so we go ahead and define them to avoid further complications and make the code more readable, so people reading it will understand what is supposed to stay constant and what isn't. I have read here and there (C programming A Modern Approach, K.N King) that we can define these two functions as macro. Since I'm somewhat new to C, I can't wrap my head

分支与跳转

由 。_饼干妹妹 提交于 2019-12-23 13:44:48
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> #1 编写一个程序读取输入，读到#字符停止，然后报告读取的空格数、换行符数和所有其他字符的数量。 #include <stdio.h> int main(void) { char ch; int kg = 0, hh = 0, qt = 0; while ((ch = getchar()) != '#') { switch(ch) { case ' ': kg++; break; case '\n': hh++; break; default: qt++; } } printf("%-5d %-5d %-5d\n", kg, hh, qt); return 0; } #2 编写一个程序读取输入，读到#字符停止。程序要打印每个输入的字符以及对应的ASCII码（十进制）。一行打印8个字符。建议:使用字符计数和求模运算符（%）在每8个循环周期时打印一个换行符。 #include <stdio.h> int main(void) { char ch; int t = 1; while ((ch = getchar()) != '#') { putchar(ch); printf("%d ", ch); if(!(t++ % 8)) { printf("\n"); } } return 0; } #4 使用if

Is getchar() equivalent to scanf(“%c”) and putchar() equivalent to printf(“%c”)?

由 梦想的初衷 提交于 2019-12-18 11:58:21
问题 Is a = getchar() equivalent to scanf("%c",&a); ? Is putchar(a) equivalent to printf("%c",a); where a is a char variable? 回答1: Generally speaking yes they are the same. But they are not in a few nitpicky ways. The function getchar is typed to return int and not char . This is done so that getchar can both all possible char values and additionally error codes. So while the following happily compiles in most compilers you are essentially truncating away an error message char c = getchar(); The

Theory Behind getchar() and putchar() Functions

由 徘徊边缘 提交于 2019-12-17 16:31:29
问题 I'm working through "The C Programming Language" by K&R and example 1.5 has stumped me: #include <stdio.h> /* copy input to output; 1st version */ int main(int argc, char *argv[]) { int c; while ((c = getchar()) != EOF) putchar(c); return 0; } I understand that 'getchar()' takes a character for 'putchar()' to display. However, when I run the program in terminal, why is it that I can pass an entire line of characters for 'putchar()' to display? 回答1: Because your terminal is line-buffered.

encode program using getchar from command line argument and putchar to send to decode

由 痞子三分冷 提交于 2019-12-12 18:21:58
问题 So I'm trying to make a encode/decode program. So far I'm stuck in the encode part. I have to be able to get a message from the command line arguments, and encode it using a seeded random number. This number will be given by the user as the first argument. My idea is to get the int from getchar and just add random number result to it. I then want to get it back to the std out so that another program can read it as an argument to decode it using the same seed. So far, I can't get the putchar

Output not displayed with usleep until a line break is given

由 耗尽温柔 提交于 2019-12-12 01:08:26
问题 I'm trying to program a simple "typewriter" effect in C, where text appears one letter at a time with a delay. Here's the function I have: #include <stdio.h> #include <unistd.h> void typestring(const char *str, useconds_t delay) { while (*str) { putchar(*(str++)); usleep(delay); } } The problem is the text doesn't actually appear until a \n is displayed. What am I doing wrong? 回答1: The output to stdout is buffered. Using \n you are forcing a flush. If you want to change this, you will need to

Can putchar print an integer?

由 天涯浪子 提交于 2019-12-11 09:14:01
问题 How can i print an integer with the help of putchar only. i want to do it without using external storage. This question was asked in a interview last year. 回答1: When faced with vague requirements on an interview, it's a good idea to express your assumptions. I would take the requirement about only being able to use putchar to mean that it is the only library function I am allowed to call. I would furthermore assume that "no external storage" meant that I could not explicitly create a buffer.

【AtCoder】ARC067

由 馋奶兔 提交于 2019-12-10 02:15:41
ARC067 C - Factors of Factorial 这个直接套公式就是，先求出来每个质因数的指数幂，然后约数个数就是 \((1 + e_{1})(1 + e_{2})(1 + e_{3})\cdots(1 + e_k)\) #include <bits/stdc++.h> #define fi first #define se second #define pii pair<int,int> #define mp make_pair #define pb push_back #define space putchar(' ') #define enter putchar('\n') #define eps 1e-10 #define MAXN 100005 //#define ivorysi using namespace std; typedef long long int64; typedef unsigned int u32; typedef double db; template<class T> void read(T &res) { res = 0;T f = 1;char c = getchar(); while(c < '0' || c > '9') { if(c == '-') f = -1; c = getchar(); } while(c >=

getchar() and putchar()

由 为君一笑 提交于 2019-12-09 17:44:14
问题 in the example: #include <stdio.h> main() { long nc; nc = 0; while (getchar() != EOF) ++nc; printf("%ld\n", nc); } I don't quite understand it. putchar() would put the character out, but why is it that after EOF it puts all the characters out, and where is it remembering all these characters? Thanks. 回答1: It's called buffering and it's done by the operating system. Usually it does line buffering where it just saves every character you put to it in memory, and then writes it all to the file

getchar() or putchar() keeps eating the first character of my input

由 狂风中的少年 提交于 2019-12-08 12:37:25
问题 edit: this question is solved. thank you for all answers This is my program: #include <stdio.h> int main(){ printf("write something : \n"); int c = getchar(); while((c = getchar()) != EOF){ if (c == ' ' || c == '\t') printf(" \n"); else putchar(c) } return 0; } everytime i run it, it works fine, but eats the first character of my input for example when i run the program the output looks like this: write something : this is a sentence. his is a sentence. the "t" is missing. why is that
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