please expain the following code line by line. // Q7. A text file, \"file.dat\"

ID: 3732447 • Letter: P

Question

 please expain the following code line by line.   // Q7. A text file, "file.dat" contains ascii data

 // 1.1  1.2

 // 1.3  1.4

 // 1.5  1.6

 // 1.7  1.8

 // 1.9  1.0

 // write code to read these numbers into an array of strusture below

 typedef struct

 { float x, y;

 } POINT;

 POINT pointarray[5];

  FILE *fp;

   fp = fopen("file.dat", "r");

   for(i=0; i<5; i++)

    fscanf(fp, "%f %f", &pointarray[i].x, &pointarray[i].y);

   fclose(fp);

   for(i=0; i<5; i++)

    printf("%f %f ", pointarray[i].x, pointarray[i].y);

  printf(" ");

 // Q8. Read the above data into a liked list. Then, delete the node

 // whose x is 1.7.

 typedef struct ll

 { float x, y;

   struct ll *nextll;

 } NODE;

 NODE rtnode, *newptr, *currentptr;

   fp = fopen("file.dat", "r");

  rtnode.nextll = NULL;

  currentptr = &rtnode;

  for(i=0; i<5; i++)

    fscanf(fp, "%f %f", &fx, &fy);

  newptr = malloc( sizeof(NODE) );

  newptr->x = fx;

  newptr->y = fy;

  newptr->nextll = NULL;

  currentptr->nextll = newptr;

  currentptr = newptr; // or currentptr = currentptr->next;

   fclose(fp);

 printf(" ");

  currentptr = rtnode.nextll;

  for(i=0; currentptr; i++)

   printf("trav ll (%u)     %f   %f ", currentptr,currentptr->x,  currentptr->y);

   currentptr = currentptr->nextll;

 printf(" ");

 // Q9. Add a node with x value 2.0 after the node whose data is 1.3.

  currentptr = rtnode.nextll;

  for(i=0; currentptr; i++)

   printf("-- trav ll (%u)    %f   %f ", currentptr,  currentptr->x,  currentptr->y);

   if( (currentptr->x > 1.299) && (currentptr->x <1.301) )

   //if( currentptr->x ==1.3 )

 printf(" 1.3 found.... ");

  newptr = malloc( sizeof(NODE) );

  newptr->x = 2.0;

  newptr->y = 2.0;

  newptr->nextll = currentptr->nextll;

  currentptr->nextll = newptr;

 printf(" 1.3 found.... breaking ... ");

  break;

   currentptr = currentptr->nextll;

 printf(" ");

  currentptr = rtnode.nextll;

  for(i=0; currentptr; i++)

   printf("trav ll (%u)   %f   %f ", currentptr,  currentptr->x,  currentptr->y);

   currentptr = currentptr->nextll;

 printf(" ");

 // Q10. Write code to approximate the area below f(x)=x*x+2

 // from x=a to b with x interval interval.

 {double x, interval, a, b,  xval, h, area;

  x = 0.000000001;

  a = 0.0;

  b = 0.5;

  area = 0.0;

   for( xval = a; xval<b; xval += x )

   {  h = xval*xval +2.0;

      area +=  h * x;

   printf("area =  %f  ", area);

 // assume x, interval, a, and b are given already

  currentptr = &rtnode;

  for(i=0; currentptr; i++)

   printf("==-- trav ll (%u)    %f   %f ",

          currentptr->nextll,  currentptr->nextll->x,  currentptr->nextll->y);

   if( (currentptr->nextll->x > 1.299) && (currentptr->nextll->x <1.301) )

   //if( currentptr->x ==1.3 )

 printf(" 1.3 found.... ");

  newptr = malloc( sizeof(NODE) );

  newptr->x = 2.0;

  newptr->y = 2.0;

  newptr->nextll = currentptr->nextll;

  currentptr->nextll = newptr;

 printf(" 1.3 found.... breaking ... ");

  break;

   currentptr = currentptr->nextll;

 printf(" ");

  currentptr = rtnode.nextll;

  for(i=0; currentptr; i++)

   printf("trav ll (%u)   %f   %f ", currentptr,  currentptr->x,  currentptr->y);

   currentptr = currentptr->nextll;

 printf(" ");

Hi i give explaination within comment itself in every line given.

Explaination :

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