Don't use the ping command. Create a socket to a remote server. Write some data to the socket.Check how much time it takes for the server to respond. The time difference can be your seed
In the function to calculate variance is (a) Average being calculated correctly ? (b) Can you please use brackets to more explicitly specify the order of the arithmetic operations
An uninitialized global variable takes the value 0. Doing a 0/0 division will give you an Arithmetic exception. I think this should solve the crashing issue.
How did you compile the program ? I also got the same compilation errors that mitrmkar got
Hi Chester I have a vague idea of what your question is , but before I dispense any advise can you please clarify your question ?
PS: Some random thoughts which may or may not help you 1. If you have an array of structs, there is no way to set arr[index] = null. What you can do is add a member to the struct definition called as isValid. Later if you want to set arr[index] = null, you can instead set arr[index].isValid = 0. In your print functions you can ignore all arr[index] where isValid is set to 1
2. If you have 2 struct variables t1 and t2 then if you write t1 = t2 , all of t1's contents will be replaced by t2 contents
Suppose I have to remove the string "tes" from United States of America
1. Check to see if I can find a t any where in United states of America 2. If do find a t then check for e and then s 3. Once I find the start index of the match, in this case 10 the end index has to be 13 4. Then from index 14 till the end of the string I copy chars one by one to positions 10,11,12 ....
I guess the tricky part of this exercise is identifying when you have a string match. Check out this algorithm. Might be of help
When you are reading from the file the value of MAX is 101. But each line has less than 101 characters . So what you want to do is something of this sort
int
main()
{
FILE *fp = fopen("mytestfile.txt","r");
char arr[100]; // Open a file
char *p;
if(fp == NULL)
{
printf("File does not exist");
return -1;
}
while(fgets(arr,100,fp)!=NULL) // Read from the file
{ // Assume each line will have less than 100 character
p = strchr(arr,'\n'); //Each line will be terminated by \n. Find the position of the \n
arr[p - arr] = '\0'; // Replace the \n by \0
printf("%s\n",arr);
strcpy(arr,"\0"); // Clear the array
}
fclose(fp);
return 0;
}
I can help you a little bit. My changes are in red
show you simple example of pipe
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <wait.h>
int main()
{
pid_t pid;
int pipe_fd[2];
if ( pipe(pipe_fd) == -1 )
{
perror("Pipe create error");
exit(1);
}
if ( (pid = fork()) == -1 )
{
perror("Fork create error");
exit(1);
}
if ( pid == 0 )
{
close(pipe_fd[0]); /* close open fd of pipe */
/* write fd of pipe */
/* Connect stdout to your pipe */
/* Then execute the grep function */
if ( write(pipe_fd[1], "this is pipe", 128) == -1 )
{
perror("Write Error");
exit(1);
}
exit(0);
}
if ( pid > 0 )
{
waitpid(pid, NULL, 0);
close(pipe_fd[1]); /* close write fd of pipe */
char buffer[14] = { 0 };
/* read fd of pipe */
/* Now execute the sort command. But I dont know how will you tell the system that you want to sort the contents in buffer */
if ( read(pipe_fd[0], buffer, 128) == -1 )
{
perror("Read error");
exit(1);
}
printf("Read string is : %s", buffer);
exit(0);
}
}
int x=[1,2,3,4,5];
printf("%u\n",x); // Address of the first element of the arry
printf("%d\n",*x); // Value of the element at the address x ie the first element of the array
So if you write the statement
y = ptr - *x;
// ptr contains an address, but *x contains a value
I ran your code and I got the correct o/p ie 10,4743
Where are you running your code ? Is it a specialized device ? One thing you could do is dont jump straight to 10,000 Go there exponentially you know first calculate the 2,4,8,16,32,64 and so on
Adding a little bit more information to gerard4143's post
Open the file (Use fopen for this) Read the first line of the file and store it in a buffer (Use fread for this) Go through the line and check if the name of the country appears in the file or not (Use strtok for this) If a match is found send the contents of the line you just read to the client or send error
Have you heard of a little known website called as google.... Try it out.... You might like it Here is what I found in just 0.23 seconds in this website
You are closing the file, the first time you enter the else statement block. So the next time you come to the else block you will not be able to write anything to the file
Instead close the file when you come out of the while loop
I think the type cast has to be done before applying the shift operator. Here is an example to show why
int main()
{
float f= 5.67;
int x= (int)f<<2;
printf("%d\n",x);
return 0;
}
If f is not typecasted before applying the shift operator then the code will not compile as shift operators cannot be applied to floating point numbers. This code does compile and produces the answer 20
In line 2 you are asking the computer to store a string in a char. So if I give the input as ABCDEFGH it will be stored in a char Then in line 3 you are telling the computer to store that char in an array .
Well to take input from the user there are many ways. The easiest one is through command line arguments The next one is through scanf() function. But this function is very dangerous, has lot of pitfalls. So you should avoid using it Another way of taking user input is to use fgets. This is the safest way, but it is slightly more complicated
I do not think that your program is crashing.... This is what happens when you enter a char other than c. Since the char is not c, the code goes to the default case, prints "press c to continue" then comes out of the switch scenario and wait for you to enter a char in response to getch() If you want to give the user another choice to enter the char, you have to put the switch inside a while loop
This is not a simple program. First step would be to i/p and then o/p a string. Then you should see if you can count the length of the string
My favorite book for C is "Let Us C" by Yashwant kanitkar It teach C from the very basic and makes no assumption about the programming capability of the reader
According to your above post the function set_number_people is not defined to be a part of any class but yet when you call it, you use an object to call the function
