while-loop | 易学教程

Looping through editTexts to check values

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问题 I have one layout with 100 blank EditTexts, all named based on their row / column IDs (e.g. box0101, box0102 etc.). I then have another layout with 100 TextViews in exactly the same layout with one letter in each, named using the same convention (answerbox0101, answerbox0102 etc.) I want to write a loop that checks box0101 against answerbox0101, and so on until either one of the boxes does not match up, or it gets to 100 and all the boxes match. I am fine with writing the logic of the loop,

scanf loop, and signal handler

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问题 Just learned about sigacation, also implemented another timer to make it more interesting. #include <stdio.h> #include <signal.h> #include <sys/time.h> volatile sig_atomic_t gotsignal; void handler(){ gotsignal = 1; } int main(){ struct sigaction sig; struct itimerval timer; timer.it_value.tv_sec = 5; timer.it_value.tv_usec = 0; timer.it_interval = timer.it_value; sig.sa_handler = handler; sig.sa_flags = 0; sigemptyset(&sig.sa_mask); setitimer(ITIMER_REAL, &timer, 0); sigaction(SIGALRM, &sig,

My first table valued function and cursor

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问题 I have this query: SELECT name, lastname FROM contestant WHERE name= 'John' AND lastname = 'Smith' I get several results from the query above and I need to use them for the following query: SELECT name, lastname,prize, city FROM draw WHERE name= name from table contestant AND lastname= name from table contestant Now I’m building a table valued function with a cursor and a WHILE so I can have a table with the results. Here’s my try, can you please help me complete it? it will be very helpful

Efficient and fast Python While loop while using sleep()

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I am attempting to communicate with a device over serial using Pyserial. As commands need to be continually sent, they have to be placed in a while loop in Python. I am currently using this code, and have taken a look at python process takes 100% CPU : while True: #do some serial sending here time.sleep(0.2) This code works. However, the sending speed is slow. I tried to make it faster by decreasing the sleep interval, but it seems to load the CPU a bit too much. In short, is there a any way to effectively iterate over a while loop forever, while still maintaining a low consumption of CPU

how to iterate though delimited values in bash

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问题 BASH input: cat test 1 a;b;c;d 2 a;b;c;d 3 a;b;c;d desired output is: 1 a 1 b 1 c 1 d 2 a 2 b 2 c 2 d 3 a 3 b 3 c 3 d it could be something quite simple for programmers. thank you. 回答1: Solution 1st: Could you please try following. awk -F'[ ;]' '{for(i=2;i<=NF;i++){print $1,$i}}' Input_file Solution 2nd: Adding another awk too now. awk '{gsub(/;/,ORS $1 OFS)} 1' Input_file 回答2: This might work for you (GNU sed): sed -r 's/^((\s*\S+\s*)[^;]*);/\1\n\2/;P;D' file Replace each ; by a newline

Perl: while with no conditional

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According to the doc , the while statement executes the block as long as the expression is true . I wonder why it becomes an infinite loop with an empty expression: while () { # infinite loop ... } Is it just inaccuracy in the doc? TLP $ perl -MO=Deparse -e 'while () { }' while (1) { (); } -e syntax OK It seems that while () {} and while (1) {} are equivalent. Also note that empty parens* are inserted in the empty block. Another example of pre-defined compiler behaviour: $ perl -MO=Deparse -e 'while (<>) { }' while (defined($_ = <ARGV>)) { (); } -e syntax OK I would say that this is just the

While in a loop in Haskell

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问题 How to code the following pseudo-code in Haskell? x=0 for (i from 0 to 100): j=0 while ( f(i,j) >0 ): x+= f(i,j) j+=1 ( f some unimportant function.) I came up with something like this: a= [x| i<-[0..100], let s = takeWhile (\k-> (f i k > 0)) [0..], j<- s, let x = f i j ] Then Sum a does the work, but I need to compute f i j two times which is a little bit redundant. Can this be done with f computed only once or some better codes that run faster? 回答1: Here's a way that only computes f once

Python looping and program restart if true

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问题 Please help as I am a true beginner and would love to learn more. I am trying to learn more about looping so take a look at this code please. # lets the user input first number num1 = float(raw_input("Enter your first number ---> ")) # lets the user input second number num2 = float(raw_input("Enter your second number ---> ")) #the next four lines sets the basic mathematical equations addAns = num1+num2 subAns = num1-num2 mulAns = num1*num2 divAns = num1/num2 # ask the user to let the program

Testing while for multiple conditions (C language)

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问题 I have to create a menu wherein if the input is not valid. It should keep asking for a valid input. I've written it below (in C) #include <stdio.h> int main() { int input = 0; printf("What would you like to do? \n 1 (Subtraction) \n 2 (Comparison) \n 3 (Odd/Even) \n 4 (Exit) \n "); scanf_s("%d", &input); while (input != 1 || input != 2 || input != 3|| input != 4) { printf("Please enter a valid option \n"); scanf_s("%d", &input); } // At this point, I think it should keep testing variable

while loop to infinity when the input of a cin is a 'dot'

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问题 I am having trouble using the cin method to acquire a variable. When the input is a number there is no problem, but when it is a special character like a dot [.], the whileloop loops into infinity. What am I doing wrong? cout << "What is your race" <<endl<<"1.Human\n2.troll\n3.zombie"<<endl; cin >> *race; while(*race<1||*race>3) { system("cls"); cout << "Wrong choice"<<endl<< "What is your race" <<endl<<"1.Human\n2.troll\n3.zombie"<<endl; cin >> *race; } I searched for the answer and i should