Segmentation Fault in C when adding an element to array

Question

I am trying to calculate result of the floor function for floats <= 9999.

#include <stdlib.h>
include <stdio.h>   
#include "string.h"
int main(int argc, char* argv[]) {
int i, j, k;
int x[1000];

for(i = 0; i < 10000; ++i){
    x[i] = i;
}

printf("Enter a float in 0..9999: ");
scanf("%d", k);

tester(x, k);
}

int tester(int* c, int k) {
printf("x[%d] = %d\n", k, c[k]);
}

When compiler came to;

for(i = 0; i < 10000; ++i){
   x[i] = i;
}

it gives segmentation fault;

x[i] = i;

here.

I have already checked similar questions about assigning segmentation fault but I couldn't find any solution way. Can anyone help?

Welcome to world of magic numbers in the code. int x[1000]; and for(i = 0; i < 10000; ++i) Time to count 0 digits. — Victor Gubin
– Victor Gubin, Commented Mar 26, 2022 at 8:13
you indexing 10.000 but your array is 1000. You should change your printf Enter a float to integer since %d in scanf interprets input as decimal. — AidenDean
– AidenDean, Commented Mar 26, 2022 at 8:15
"%d" (integer in decimal format) is wrong format specifier for float – you need to use "%f" instead, otherwise undefined behaviour. — Aconcagua
– Aconcagua, Commented Mar 26, 2022 at 8:16
The mismatch between 1000 and 10000 is the reason why one should use constants for – and for iterating over arrays preferrably deduce the size from the array itself: sizeof(array)/sizeof(*array). — Aconcagua
– Aconcagua, Commented Mar 26, 2022 at 10:12

Nicholas Weston · Accepted Answer · 2022-03-26 08:13:58Z

2

The array x is of length 1,000, but you're treating it in the loop as if it's of length 10,000. Accessing x[i] for i greater than or equal to 1,000 is undefined behaviour because the index is out of the array's range.

Thus, a segmentation fault is occurring because your program is accessing memory that it is not allowed to access.

answered Mar 26, 2022 at 8:13

Nicholas Weston

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Comments

Dharman · Accepted Answer · 2022-03-26 08:28:25Z

0

The variable k is initialised and when getting input "&" is missing in the scanf statement. This might have come under segmentation fault since the value "k" is passed in the function tester(). Generally in C lang, we get input with "&", unless if it is a string you don't necessarily mention that in the scanf statement!!.

edited Mar 26, 2022 at 8:28

Dharman♦

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answered Mar 26, 2022 at 8:22

Haritha Ramsureshkumar

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