Question

I have the problem with the code, when I input 0xef1e4 0x5 3, it doesn't execute anything.

I get the code from https://www.chegg.com/homework-help/programming-in-c-4th-edition-chapter-11-problem-6e-solution-9780321776419

but it seems error

#include <stdio.h>
int intSize(void)
{
unsigned int n= ~0;
int counter = 4;
while(n>0)
{
n=n>>1;
counter++;
}
return counter-1;//account for sign bit
}
//function to calculate the min number of bits needed to represent a value
int numberOfBits(unsigned int x)
{
int sizeOfInt=intSize();
int counter = 0;
unsigned int temp = 1<<(sizeOfInt - 1);
while((temp | x) != x)
{
temp = temp >>1;
counter++;
}
return sizeOfInt - counter;
}

//function to return the n right most bits
int rightMost(int pattern, int n)
{
int temp, rightMost;
temp = ~0;
temp = temp<<n;
temp = ~temp;
rightMost = pattern &temp;
return rightMost;

}

int bitpat_search(int source, int pattern, int n)
{
int pRightMost, sourceBits, inder, res, index;
pRightMost = rightMost(pattern, n);
sourceBits = numberOfBits(source);
index=(sourceBits - n);
res=-1;
while(index>=0)
{
if((rightMost(source,n)^pRightMost)==0)
res = index;
source =source>>1;
index=index-1;
}
return res;
}
int main(void)
{
int index, source, pattern, n;
printf("\nEnter 3 arguments(source pattern n):");
scanf("%i %i %i, &source,&pattern, &n");
printf("The %i most bits of %i is %i\n", n, pattern, rightMost(pattern, n));
index = bitpat_search(source, pattern, n);
printf("Pattern is at index %i\n", index);
return 0;
}

Answer 1

Here is the code provided above with slight modification while taking input now it executes. just modified the scanf statements look for bold text in the code for changed lines

C CODE

#include <stdio.h>
int intSize(void)
{
unsigned int n= ~0;
int counter = 4;
while(n>0)
{
n=n>>1;
counter++;
}
return counter-1;//account for sign bit
}
//function to calculate the min number of bits needed to represent a value
int numberOfBits(unsigned int x)
{
int sizeOfInt=intSize();
int counter = 0;
unsigned int temp = 1<<(sizeOfInt - 1);
while((temp | x) != x)
{
temp = temp >>1;
counter++;
}
return sizeOfInt - counter;
}

//function to return the n right most bits
int rightMost(int pattern, int n)
{
int temp, rightMost;
temp = ~0;
temp = temp<<n;
temp = ~temp;
rightMost = pattern &temp;
return rightMost;

}

int bitpat_search(int source, int pattern, int n)
{
int pRightMost, sourceBits, inder, res, index;
pRightMost = rightMost(pattern, n);
sourceBits = numberOfBits(source);
index=(sourceBits - n);
res=-1;
while(index>=0)
{
if((rightMost(source,n)^pRightMost)==0)
res = index;
source =source>>1;
index=index-1;
}
return res;
}
int main(void)
{
int index, source, pattern, n;
printf("\nEnter source (hexadecimal):");
scanf("%i, &source");
printf("\nEnter pattern (hexadecimal):");
scanf("%i,&pattern");
printf("\nEnter n (hexadecimal):");
scanf("%i,&n");
printf("The %i most bits of %i is %i\n", n, pattern, rightMost(pattern, n));
index = bitpat_search(source, pattern, n);
printf("Pattern is at index %i\n", index);
return 0;
}

OUTPUT OF SCREENSHOT

Enter source (hexadecimal):Oxefle4 Enter pattern (hexadecimal):0x5 Enter n (hexadecimal):0x3 The 1 most bits of is Pattern is at index 0 - - - - - - - - - - - - - - - - - - - - - - - - - - - Process exited after 12.38 seconds with return value o Press any key to continue...

Enter source (hexadecimal):Oxefle4 Enter pattern (hexadecimal):0x5 Enter n (hexadecimal):0x3 The 1 most bits of is Pattern is at index 0 - - - - - - - - - - - - - - - - - - - - - - - - - - - Process exited after 12.38 seconds with return value o Press any key to continue...