Need help fixing Segmentation Fault - c

Question

I had this working a second ago but accidentally broke it. Can anyone help me fix it? I'm getting a Segmentation Fault so I assume I messed up the pointers at some point. It's supposed to generate a bunch of random numbers depending on user input.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[])
{
unsigned int mySeed; // creates our variables
unsigned int taps[2];
unsigned int temp[2];
unsigned int myToggle;
FILE *fp;//opens the file
fp = fopen("random.txt", "w");//sets the file to open equal to this file
int TapInputs = 1;
int count = 0;
int tap;
int myNewNumber = 0;
mySeed = atoi(argv[1]);
if(atoi(argv[1]) > 0) //Error checking for negative inputs.
{
printf("Please enter the taps you'd like to use : ");//prompts user to input the taps and then makes sure theyre in range
while(TapInputs)
{
scanf("%d",&tap);
if((tap > 0)&&(tap < 33))
{
*(taps+count)=tap;
}
else if(tap == -1) // when we find -1 we do this
{
TapInputs = 0;
}
else if(tap > 32)
{
exit(0);
}
count++;
}
printf("How many numbers do you want to generate: "); //prompts user to input the number of numbers to use
scanf("%d", &myNewNumber);
while (myNewNumber < 0)// error checking for positive inputs
{
printf("How many numbers do you want to generate: ");
scanf("%d", &myNewNumber);
}
printf("\nRandom Numbers:");
while(myNewNumber)//creates number equal to the user input number in the previous step
{
temp[0] = mySeed; // makes temp1 the seed
temp[1] = mySeed; // makes temp2 the seed
temp[0] = (temp[0] >> taps[0]) & 1; // checks and sets the bit
temp[1] = (temp[1] >> taps[1]) & 1; // checks and sets the bit
myToggle = (temp[0] ^ temp[1]); // here we xor the temp1 and 2
mySeed = (mySeed << 1) ^ myToggle; // use bittoggle to shift the seed and generate a new number
fprintf(fp, "%d\r\n", mySeed); // wrties the generated number into the file
printf("\n%d", mySeed); // prints the number
myNewNumber -= 1;
}
fclose(fp); // closes file, creates a new line and returns 0 to the fucntion
printf("\n");
return 0;
}
else
{ // if the number the user input was 0 we will end our program
exit(0);
}
}
The fault happens immediately upon execution.

Answer 1

This piece of code :
while(TapInputs)
{
scanf("%d",&tap);
if((tap > 0)&&(tap < 33))
{
*(taps+count)=tap;
}
else if(tap == -1) // when we find -1 we do this
{
TapInputs = 0;
}
else if(tap > 32)
{
exit(0);
}
count++;
}
is executed until you find TapInputs to be false, or in other words 0. This will happen only if you give -1 as an input to scanf("%d", &tap). Until then, you will keep reading and also incrementing count.
But some lines above, you have declared
unsigned int taps[2];
and in your while loop you do
*(taps+count)=tap;
So, if you have read tap enough times and keep finding it between 0 and 33, until you find it -1, count will have increased enough to get your array out of bounds.

Answer 2

I think problem is in this line , mySeed = atoi(argv[1]);
you have to do something like this,
you can put the code from that in an if condition ,
if(agrc>1)
{
mySeed = atoi(argv[1]);
---------------------
--------------------
}
I have tested...it is working
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[])
{
unsigned int mySeed; // creates our variables
unsigned int taps[2];
unsigned int temp[2];
unsigned int myToggle;
FILE *fp;//opens the file
fp = fopen("random.txt", "w");//sets the file to open equal to this file
int TapInputs = 1;
int count = 0;
int tap;
int myNewNumber = 0;
if(agrc>1)
{
mySeed = atoi(argv[1]);
if(atoi(argv[1]) > 0) //Error checking for negative inputs.
{
printf("Please enter the taps you'd like to use : ");//prompts user to input the taps and then makes sure theyre in range
while(TapInputs)
{
scanf("%d",&tap);
if((tap > 0)&&(tap < 33))
{
*(taps+count)=tap;
}
else if(tap == -1) // when we find -1 we do this
{
TapInputs = 0;
}
else if(tap > 32)
{
exit(0);
}
count++;
}
printf("How many numbers do you want to generate: "); //prompts user to input the number of numbers to use
scanf("%d", &myNewNumber);
while (myNewNumber < 0)// error checking for positive inputs
{
printf("How many numbers do you want to generate: ");
scanf("%d", &myNewNumber);
}
printf("\nRandom Numbers:");
while(myNewNumber)//creates number equal to the user input number in the previous step
{
temp[0] = mySeed; // makes temp1 the seed
temp[1] = mySeed; // makes temp2 the seed
temp[0] = (temp[0] >> taps[0]) & 1; // checks and sets the bit
temp[1] = (temp[1] >> taps[1]) & 1; // checks and sets the bit
myToggle = (temp[0] ^ temp[1]); // here we xor the temp1 and 2
mySeed = (mySeed << 1) ^ myToggle; // use bittoggle to shift the seed and generate a new number
fprintf(fp, "%d\r\n", mySeed); // wrties the generated number into the file
printf("\n%d", mySeed); // prints the number
myNewNumber -= 1;
}
fclose(fp); // closes file, creates a new line and returns 0 to the fucntion
printf("\n");
return 0;
}
else
{ // if the number the user input was 0 we will end our program
exit(0);
}
}
}