Question

Question 2. The following code defines an array size that sums elements of the defined array through the loop.

1. Analyze the following code, and demonstrate the type of error if found?
2. What we can do to make this code function correctly?

#include <stdio.h>

#define A 10

int main(int argc, char** argv) {

int Total = 0;

int numbers[A];

for (int i=0; i < A; i++)

numbers[i] = i+1;

int i =0;

while (i<=A){

   Total += numbers[i];

   i++;

}

printf("Total =%d\n", Total);

return 0;

}

Answer 1

Answer

Here is your answer, if you have any doubt please comment, i am here to help you.

1)

#include <stdio.h>

#define A 10

int main(int argc, char** argv) {

int Total = 0;

int numbers[A];

for (int i=0; i < A; i++)

numbers[i] = i+1;

int i =0;

while (i<=A){

   Total += numbers[i];

   i++;

}

printf("Total =%d\n", Total);

return 0;

}

When this code run in c, we will get the following error.

actual expect result is 55.

This happen because the following code

//This is the error happening statement in the above program
//In C there is no exception happening in indexoutofbound
//it will access some other memory location allotted for the array.
//That means indexoutofbound will return some garbage value here.

while (i<=A){  //limit should be lessthan 10 and not equal 10, because index start at 0, 
//in the assignment statement, we can see we only get value <10 not <=10. So,
//If access the index of 10 will be garbage.
   Total += numbers[i];

   i++;

}

Access non allocated location of memory: The program can access some piece of memory which is owned by it.

2) To make it functional just use the 'less than'(<) not use 'less than or equal'(<=) in while loop.

Here is final code and result.

#include <stdio.h>

#define A 10

int main(int argc, char** argv) {

int Total = 0;

int numbers[A];

for (int i=0; i < A; i++)

numbers[i] = i+1;

int i =0;

while (i<A){  //just change here < instead of <=

   Total += numbers[i];

   i++;

}

printf("Total =%d\n", Total);

return 0;

}

output

Any doubt please comment,

Thanks in advance