This C code is supposed to create some random numbers and print them and then sort them and print them again, but it just prints the sorted numbers. Could any body help me?
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
int main(){
int i, j, k;
float temper;
time_t t;
float grades[1000];
fflush(stdout);
printf("Here are the number\n");
srand(time(&t));
for(i=0;i<1000;i++){
grades[i]=rand();
printf("%f\n", grades[i]);
}
for(i=0;i<1000;i++){
int swap=0;
for(j=i;j<1000;j++){
if(grades[i]>grades[j]){
temper=grades[i];
grades[i]=grades[j];
grades[j]=temper;
swap=1;
}
}
}
printf("sorting is done");
for(i=0;i<1000;i++){
printf("%f\n", grades[i]);
} }
Your program is working correctly. Try changing everything from 1000 to 10 just to test and see for yourself.
What is happening is that it is printing everything out so quickly that the first 1000 is off the page.
The code is correct.
Try a small size to array,
write all the logs to a file.
Code worked fine for me too. Maybe your terminal is not storing enough lines for you to see the beginning of the output. You can change that in the settings for your terminal. Or you can cat them to a file instead. There is an easy option to do so if you google it. Also, add in another printf in between as a marker that is obvious like:
printf("+++++++++++++++++++++++++++ here is the break point ++++++++++++++++");
It will make it that much harder to miss it. Good luck!
PS: to cat your output to a file simply type '> filename' when running the program. I called mine math.c so when I ran I typed:
'$./math > file'
And the whole output in in a file named 'file'
Related
Hello and thank all who bothered to read. I am currently trying to execute a program in c that contains a function with this for loop.
#include <stdio.h>
#include <string.h>
int main(int argc, char **argv){
int i, goal;
char resp[1];
printf("How many people would you like to ask?");
scanf("%d" ,&goal);
for(i = 0; i < goal; i++){
printf("-Person %d: Would you like to register to vote?\n",(i+1));
scanf("%s", resp);
if((strcmp(resp, "n"))==0){
printf("\nOk.\n");
}
else if((strcmp(resp, "y"))==0){
printf("\nRegistering...\n");
}
}
printf("\n%d people asked! Taking a break.\n", goal);
}
Yet for some reason, when I run the program, after pressing n for all of the runs, the for loop does not increment, leading to an infinite loop on the final run.
I have tried changing the for loop to a while loop with the same results and have also tried the y option for the last time which led to a whole host of other issues. In order to get the goal value I am using scanf though when I tried using fgets I still came into the same flawed result or worse. I ran this code into a debugger and when executing the program line by line it works fine, but running it normally seems to be the issue. Any help is appreciated and I am willing to clarify or expand on my code. This is my first post here so apologies if this has been asked 50 trillion times.
I'm a novice programmer getting introduced to C and I'm missing something fundamental about the way my scanf() works. I want to read a single int from the keyboard with code like this:
#include <stdio.h>
#include <stdlib.h>
int main(void) {
int userBookSelection;
scanf("%i", &userBookSelection);
printf("Printing userBookSelection: %i", userBookSelection);
return EXIT_SUCCESS;
}
When I run the code, the console stays black until I stop debugging. There is never a cursor waiting for keyboard input. When I stop debug I can see this output in the console, same every time:
Printing userBookSelection: 2130567168
I'm debugging in Eclipse with MinGW GCC compiler on Windows. The code syntax seems to be correct -- is it possible there's something wrong in my build path to make this happen? I need to know why scanf() isn't reading for keyboard input.
So I've gotten a line of code from my professor which takes care of this bug -- whether it's a necessary solution particular to Eclipse and/or MinGW I'm not sure. In any case, here's the code with the additional line:
int main(void) {
int userBookSelection;
setvbuf (stdout, NULL, _IONBF, 0);//<---The magic line
scanf("%i", &userBookSelection);
printf("Printing userBookSelection: %i", userBookSelection);
return EXIT_SUCCESS;
}
I'd appreciate any additional wisdom on what's going on, what setvbuf() is doing and how scanf() works more fundamentally.
In the following simple program after the user inputs an integer the command line remains a flashing prompt. When I exit the program the answer is then printed out. Why is this and how can I fix it?
//powers of 2
#include <stdio.h>
int main(void){
int a,b=1,i;
printf("What power of 2?\n");
scanf("%i\n",&a);
for (i=0; i<a;i++)
{
b=b*2;
}
printf("the answer is: %i\n",b);
return 0;
}
Try remove the \n in your scan :
scanf("%i",&a);
Remove \n from scanf. After that I compiled your program and it worked properly.
#include <stdio.h>
#include <cstdlib>
rec();
main()
{
int a, fact;
char q, n, y;
printf("\nEnter any number ");
scanf("%d", & a);
fact = rec(a);
printf("Factorial value = %d\n", fact);
printf("do you want to exit.....(y/n):");
scanf("%s" ,&q);
if (q == 'n')
{
system("cls");
main();
}
else
return 0;
}
rec(int x)
{
int f;
if (x == 1)
return 1;
else
f = x * rec(x - 1);
return f;
}
I'm using code blocks but I don't know how to clear the screen. I searched then found system("cls"); within header file #include<cstdlib>, but it shows the error cstdlib: no such file of directory. What should I do ?
Change
#include <cstdlib>
to
#include <stdlib.h>
cstdlib is a C++ header file, and thus will be unusable in C.
Clearing the screen is outside the purview of a normal C program. It depends on the operating system.
For windows, you should look into conio.
For unix, look into curses or termios.
system() always launches a sub-shell which may or may not have any effect on the environment of the parent program. You do need a system-call, but not a system() call.
I didn't always know this. I once (long ago) suggested in comp.lang.c that someone should try system("exit"); to close the window around the DOS program. But that, of course, cannot work. And I was quickly advised to test my code before posting. :)
you have lots of problems in your code....
but for the specific problem, try #include <stdlib.h>
use the #include<stdlib.h> that's where the clear screen function is defined.
To use system("cls") you need the header <iostream>. This will allow all system() types to execute. Unsure if it is a C++ header file, but it works for the compiler that I use.
I am trying to launch a program from another program.
Here is the code below
Figure :1
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include<string.h>
int main()
{
printf("Before Execution \n");
system("c:\\Rasmi Personal\\PERSONAL\\C\\Code Block\\C_Test\\bin\\Debug\\C_Test.exe");
printf("\nAfter Execution \n");
return 0;
}
In c:\Rasmi Personal\PERSONAL\C\Code Block\C_Test\bin\Debug\C_Test project contains the code is
Figure 2:
#include <stdio.h>
int main()
{
int x = 10;
while( x --> 0 ) // x goes to 0
{
printf("%d\n", x);
} return 0;
}
But while executing the 1st program (Figure 1) the output comes as below.
Before Execution
'c:\Rasmi' is not recognized as an internal or external command,
operable program or batch file.
After Execution
Please help me in solving this.
PS:- I am using CODE::BLOCKS in Windows XP.
You're using path names with spaces in them. Everything gets more confusing when you do that, and you have to add quotes around the right things in the right places to get anything to work.
I recommend using path names without spaces in them.
If you still want to try to make this work with spaces in your path names, the following might do it:
system("\"c:\\Rasmi Personal\\PERSONAL\\C\\Code Block\\C_Test\\bin\\Debug\\C_Test.exe\"");