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Closed 9 years ago.
I am trying to randomize a variable and then trying to use it in the functions where I want to use. But, when I put the randomized variable in for loop like below and when I use that in the function that I want to then it gives me error.
#include <stdlib.h>
#include "time.h"
void main (void) {
for (int i = 0; i < 4; i++) {
srand( time(NULL ));
float r;
r = rand()*1000;
}
write(abc, r);
read(abc, r);
write(xyz, r);
read(xyz, r);
}
So, when I use r from the for loop I get the error below:
In function 'void sim()':
'r' was not declared in this scope
But, when I remove r from the for loop then there is not any error. But, I want for loop so as to have different data for every write function.
Any suggestions would be appreciated.
r is a local variable for the loop and it is not visible outside of the loop. To fix this place its declaration(float r;) before the loop.
The scope of r is only inside the for loop. Declare it prior to the loop, and you'll be good to go.
Related
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Closed 9 years ago.
I have to write a program in c language and this is the code : The problem is that when I try to compile it it says : syntax error before return .Where is my error?
#include <stdio.h>
int main (void)
{
char i,c2,j;
int c=4;
i=j=3;
while (++i <=c)
{
int j=1;
printf("\n Nr1=%c Nr2=%d",64+i,c2);
} do;
return 1;
}
Remove the do from your code. Just while (++i <= c) { /* ... */ };
You are redeclaring j inside the while loop. Remove int j=1;
and remove the do; at the end of your while
There is no such thing as while ... do loop in C. There are while loops or do ... while loops.
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Closed 10 years ago.
I'm trying to initialise all elements of a 3D array "A". The array consists of 2000x100x4 integer elements of the 3D array and is stored in row-major order. Each index at position [i,j,k] in "A" must be initialised with the value i*i*i + j*j*j.
How can I do this using for loops? Any suggestions? Thanks.
for(i=0;i<2000;i++)
for(j=0;j<100;j++)
for(k=0;k<4;k++)
A[i][j][k]= (i*i*i) + (j*j*j);
I hope I understood your question correctly. Or were you looking for something else?
It's not something hard to do:
int A[2000][100][4];
int i,j,k;
for (i=0;<2000;i++)
{
for (j=0;j<100;j++)
{
for (k=0;k<4;k++)
{
A[i][j][k] = i*i*i + j*j*j;
}
}
}
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Closed 10 years ago.
I have written a code to find nth ugly number(a number which has at least one prime factor grater than 5) where n is a given input. my program runs well if the user inputs something less than 240. But if input gets bigger than that, program crashes!. My question is if it is a time consuming problem then it should take time but why the program crashes? I have used double everywhere so it might not be the matter of variable capacity!!
my code is below:
#include<stdio.h>
#include<math.h>
double primes[1000]={2,3,5};
int serial=3;
double next_prime()
{
double f=primes[serial-1]+2;
int count;
for(count=1;primes[count]<=(sqrt(f)+1) && count<serial;count++){
if(fmod(f,primes[count])==0){
f+=2;
count=1;
}
}
return primes[serial++]=f;
}
int main()
{
double ugly_serial=12,ugly_number=16,j;
int c,count,loop,input;
scanf("%d",&input);
while(ugly_serial<input)
{
loop=0;
for(c=3;primes[c-1]<=sqrt(ugly_number);c++){
j=next_prime();
}
for(count=3;count<c;count++){
if(fmod(ugly_number,primes[count])==0){
loop=1;
break;
}
}
if(loop==0){ugly_serial++;}
ugly_number++;
}
printf("%.0lf",ugly_number);
return 0;
}
I have compiled and run your code. The program works fine with all the input I have tried, including 56565.
Are you sure you are running the most recently compiled version of your program?
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Closed 10 years ago.
i am getting runtime error sigsegv, i don't understand the problem with this code.
this is a program to match initial substring with with array of string having maximum priority.
#include<stdio.h>
#include<limits.h>
int main() {
int T,i,N;
char si[T][1000];
long vi[T];
scanf("%d",&T);
for(i=0;i<T;++i)
scanf("%s%ld",&si[i],&vi[i]);
scanf("%d",&N);
while(N--) {
char str[1000];
scanf("%s",str);
int j,maxPindex=-1;
long maxPriority=LONG_MIN;
int l=strlen(str);
for(j=0;j<T;++j) {
if(strlen(si[j])>=l && strncmp(str,si[j],l)==0 && vi[j]>maxPriority) {
maxPriority=vi[j];
maxPindex=j;
}
}
//free(str);
if(maxPindex==-1) printf("NO\n");
else printf("%s\n",si[maxPindex]);
}
return (0);
}
It crashes already when it tries to create the variable "si". A C variable inside a function, such as the variable "T", starts with random garbage as its value. For example, it could contain 918128238. Then, when trying to create "si", this would be a very large array, and it doesn't fit.
You need to read a value for "T" before "si" and "vi" are created. That is, move your scanf before the declarions of "si" and "vi".
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Closed 10 years ago.
Ok this is a simple C code but for some unknown reason the program refuse to compile and give segmentation fault 11 Please help me
#include <stdio.h>
typedef struct {
int P_answer[9];
int number;
} BOX;
int main()
{
BOX Matrix[8][8];
int i,j;
int k;
for(i=0;i<9;i++){
for(j=0;j<9;j++){
Matrix[i][j].number=0;
Matrix[i][j].P_answer[0]=1;
Matrix[i][j].P_answer[1]=2;
Matrix[i][j].P_answer[2]=3;
Matrix[i][j].P_answer[3]=4;
Matrix[i][j].P_answer[4]=5;
Matrix[i][j].P_answer[5]=6;
Matrix[i][j].P_answer[6]=7;
Matrix[i][j].P_answer[7]=8;
Matrix[i][j].P_answer[8]=9;
}
}
}
Matrix is an 8-by-8 array; each of your loops goes through 9 iterations.
The indexes of an array go from 0 to (size-1).
In your for-loops you go from 0 to size.
That's the reason of your segmentation fault.