C Sample Code. Nyoman Bogi Aditya Karna Sisfo IMTelkom

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1 Dynamic Array C Sample Code Nyoman Bogi Aditya Karna Sisfo IMTelkom bogi@imtelkom.ac.id Institut Manajemen Telkom

2 /* This program will read the data file (text file) */ /* dissect into a dynamic array */ /* and produce the result both in data measurement */ /* and error.log file */ /* input file name is given as a command line argument */ /* */ #include <stdio.h> #include <string.h> #include <stdlib.h> #include <math.h> #define MAX_STUDENT 30 #define MAX_QUESTION 200 struct student char studentid[10]; /* student ID number as a string */ int *answers; /* ptr to dynamic array of grades */ int rawscore; /* calculated raw score */ ; typedef struct student student; /* assign student structure as a new var type*/ int main(int argc, char *argv[]) /* FUNCTION PROTOTYPE */ FILE *open_file (char *, char *); void get_header (FILE *, char []); int *get_solution (FILE *, int *); int get_student (FILE *, student [], int, int *); student assign_student (char [], char [], int, int *); void statistic (student [], double [], int, int, int *); void print_out (student [], double [], char [], int, int, int *); /* VARIABLE DECLARATION */ char *filename, /* name of the text file (data file) */ header[85]; /* header of the data file */ FILE *fp, /* pointer to the data file */ *error; /* pointer to error.log file */ int *solution; /* array of correct solution */ int no_of_question, /* number of correct solution */ no_of_student; /* number of valid student taking the exam */ student examtakers[max_student]; /* array of the student's information*/ double statistics[6];/* contain all statistic measurements */

3 /* mean, std_dev, median for all students */ /* mean, std_dev, median for every question */ /* START MAIN PROGRAM */ if (argc==2) filename=argv[1]; else fprintf(stderr,"usage : project filename\n"); fp=open_file(filename, "r"); error=open_file("error.log","w"); fclose(error); /* flush error log file */ get_header(fp, header);/* obtain the header of the text file */ solution=get_solution(fp, &no_of_question); /* obtain the correct solution in array and return a pointer to solutions array */ no_of_student=get_student(fp, examtakers, no_of_question, solution); /* obtain all student information and return the number of valid students found*/ statistic(examtakers, statistics, no_of_student, no_of_question, solution); /* calculate all statistic measures */ /* and put them in statistics array */ print_out(examtakers, statistics, header, no_of_student, no_of_question, solution); /* print the student report & summary report */ fclose(fp); return 0; /* function : open a file, given the name of the file and the mode to open */ /* return a pointer to the file if success (exist and readable) */ FILE *open_file(char *file_name, char *mode) FILE *fp; if ((fp=fopen(file_name,mode)) == NULL) /* error checking for file exist. */ fprintf(stderr,"file not found\n"); return fp; /* return a file pointer if success (file exist) */ /* function : get the file header (the first line of a text file) */ /* return the file header in string (array of char)*/

4 void get_header(file *file_pointer, char file_header[]) if (fgets(file_header,85,file_pointer) == NULL) /* error checking */ fprintf(stderr,"file empty\n"); /* if file is empty */ if (file_header[79]!='1') fprintf(stderr,"no header found\n"); /* given file has no header */ file_header[78]='\0'; /* eliminate new line char at [80] and '1' at [79]*/ /* function : get the solution part of the text file */ /* return a pointer to an array (int) contain the correct solution */ /* it also return the number of correct solution (call by reference)*/ int *get_solution(file *file_pointer, int *no_of_question) char line[85], /* each line of type-2 data */ solution[max_question]=' '; /* contain all correct solution in string */ /* (for temporary storage only) */ int i, /* used for iteration */ *solution_data; /* ptr to solution array */ fgets(line,85,file_pointer); /* get the first line of type-2 data */ /* to obtain the number of solution */ if (line[79]!='2') /* check if it's type-2 data */ fprintf(stderr,"error on solution part\n"); sscanf(line,"%d",no_of_question); /* get the number of correct solution */ if (*no_of_question<=0 *no_of_question>max_question) /* check no_of_question validity */ fprintf(stderr, "invalid number of questions\n"); fprintf(stderr, "it should be positive and less than MAX_QUESTION\n"); if ((solution_data=(int *) calloc(*no_of_question, sizeof(int)))==null) fprintf(stderr, "error allocating memory\n"); /* allocate memory for all solution */

5 strncpy(solution, line+10, 50); /* get the solution part (50 char) */ for (i=0;i<*no_of_question/50;++i) /* if there are more solution */ fgets(line,85,file_pointer); /* read them */ if (line[79]!='2') /* but check if it's type-2 data */ fprintf(stderr,"error on solution part\n"); strncat(solution, line+10, 50); /* concatenate all solution */ /* (still in string format) */ if (solution[*no_of_question]!=' ') fprintf(stderr,"too many solution records\n"); for (i=0; i<*no_of_question; ++i) solution_data[i]=solution[i]-48; /* convert solution string into numeric*/ return solution_data; /* function : assign a new student in a student structure */ /* including raw score calculation */ /* return the student structure */ student assign_student(char student_id[], char student_solution[], int no_of_question, int *solution) int i; /* used for iteration (counter) */ student new_student; /* variable type student structure */ strcpy(new_student.studentid,student_id); /*assign student ID to the struct*/ new_student.rawscore=0; /* initialize student's raw score*/ if ((new_student.answers=(int *) calloc(no_of_question, sizeof(int)))==null) fprintf(stderr, "error allocating memory\n"); for (i=0; i<no_of_question; ++i)/* convert student solution into numeric */ new_student.answers[i]=student_solution[i]-48; if (new_student.answers[i]==solution[i]) /* calculate raw score */ new_student.rawscore++; return new_student;

6 /* function : get the student information (student ID and solution card) */ /* and construct a data structure (array of struct) */ /* return a pointer to the struct and the number of valid exam takers*/ int get_student(file *file_pointer, student examtakers[], int no_of_question, int *solution) FILE *error; int i, /* used for iteration (counter) */ student_no=0; /* student counter */ char mainline[85], /* 1st line of type-3 for each student */ line[85], /* each line of type-3 data */ ID[10], ID_comparator[10],/* each of the student ID */ answer[max_question]; /* each of the student answer */ /* all three variable above are temporary */ answer[0]='\0'; /* initialize end of string at the beginning of answer */ ID[0]='\0'; /* initialize end of string for both */ ID_comparator[0]='\0'; /* string ID for equal comparison (using strcmp) */ while (!feof(file_pointer) line[0]=='\n') if (!strcmp(id, ID_comparator)) fgets(mainline,85,file_pointer); /* take 1st line of each student */ else strcpy(mainline,line); if (mainline[79]!='3') /* check if it's type-3 data */ fprintf(stderr,"error on student record\n"); sscanf(mainline,"%s",id);/*get the student ID number (the first-10 char)*/ strcpy(id_comparator, ID); /* set the 2 ID the same in case of */ /* no_of_question < 50 (only 1 line type-3) */ strncat(answer, mainline+10, 50);/*get the student answer (11-50th char)*/ for (i=0;i<no_of_question/50;++i) /* if there are more solution */ fgets(line,85,file_pointer); /* take the next line of type-3 data*/ if (line[79]!='3') /* check if it's type-3 data */ fprintf(stderr,"error on student record\n"); sscanf(line,"%s",id_comparator);/* get the ID for comparison */ if (strcmp(id, ID_comparator)) break; strncat(answer, line+10, 50);/* get the student answer (11th-50th char)*/ if (strcmp(id, ID_comparator) line[0]=='\n') error=open_file("error.log", "a");

7 fprintf(error, "Student with ID : %s does not have enough answers\n", ID); fclose(error); /* put invalid student answer in error.log file */ else /* if student answer valid : assign as a new student in struct */ examtakers[student_no]=assign_student(id, answer, no_of_question, solution); student_no++; answer[0]='\0'; /* flush answer */ return (student_no-1); /* function : calculate all necessary statistical measures */ /* (e.g. mean, median, and standard deviation) */ /* put them in 1 array (double statistics[6]) */ void statistic(student examtakers[], double statistics[], int no_of_student, int no_of_question, int *solution) int i, j; /* used for iteration (counter) */ double temp, /* temporary storage for sorting purposes */ question[max_question]=0.0, /* contain the percent. of correct answer */ sum=0.0, /* sum of all score */ sqr_xi=0.0; /* x[i] * x[i] for standard deviation calc. */ student temp_student; /* temporary variable with student structure */ /* for sorting purposes */ for (i=0; i<no_of_student; i++) sum+=examtakers[i].rawscore; sqr_xi+=examtakers[i].rawscore*examtakers[i].rawscore; for (i=0; i<no_of_student-1; i++) /* buble sorting the score to find */ for (j=no_of_student-1; j>i; --j)/* the median of the raw scores */ if (examtakers[j-1].rawscore>examtakers[j].rawscore) temp_student=examtakers[j-1];/* swap between student [j-1] and [j]*/ examtakers[j-1]=examtakers[j]; examtakers[j]=temp_student;

8 statistics[0] =(float) sum/no_of_student; /* calc. the mean */ statistics[1] =(float) sqrt((sqr_xi-no_of_student* statistics[0]*statistics[0])/(no_of_student-1)); /*calc. the std_dev */ /* start to calculate median */ if (no_of_student % 2 == 0) /* no_of_student is an even number */ statistics[2] =(float) (examtakers[no_of_student/2-1].rawscore+ examtakers[no_of_student/2].rawscore)/2.0; else /* no_of_student is an odd number */ statistics[2] =(float) examtakers[no_of_student/2].rawscore; sum =0; /* initialize to reuse sum and sqr_xi */ sqr_xi=0; for (i=0; i<no_of_question; i++) for (j=0; j<no_of_student; j++) if (solution[i]==examtakers[j].answers[i]) question[i]++; question[i]=100*(float)question[i]/no_of_student; for (i=0; i<no_of_question; i++) sum+=question[i]; sqr_xi+=question[i]*question[i]; for (i=0; i<no_of_question-1; i++) /* buble sorting the array to find */ for (j=no_of_question-1; j>i; --j)/* the median of the percentage */ if (question[j-1]>question[j]) temp=question[j-1]; /* swap between score [j-1] and [j] */ question[j-1]=question[j]; question[j]=temp; statistics[3] =(float) sum/(float)no_of_question; /* calc. the mean */ statistics[4] =(float) sqrt((sqr_xi-no_of_question*statistics[3]* statistics[3])/(no_of_question-1)); /*calc. the std_dev */ /* start to calculate median */ if (no_of_question % 2 == 0) /* no_of_question is an even number */ statistics[5] =(float) (question[no_of_question/2-1]+ question[no_of_question/2])/2.0;

9 else /* no_of_question is an odd number */ statistics[5] =(float) question[no_of_question/2]; /* function : print out student report and summary report */ void print_out(student examtakers[], double statistics[], char header[], int no_of_student, int no_of_question, int *solution) int i,j, /* used for iteration (counter) */ correct=0; /* as a counter of correct answer */ student temp; /* temporary variable with student structure */ /* for sorting purposes */ /* sorting the student based on ID number */ for (i=0; i<no_of_student-1; i++) for (j=no_of_student-1; j>i; --j) if (strcmp(examtakers[j-1].studentid,examtakers[j].studentid)>0) temp=examtakers[j-1]; examtakers[j-1]=examtakers[j]; examtakers[j]=temp; printf("%s\n\n", header); printf("student REPORT :\n"); printf(" Student ID raw score percent correct \n"); for (i=0; i<no_of_student; ++i) printf("%10s%22d%25.2f\n",examtakers[i].studentid,examtakers[i].rawscore, 100*((float)examTakers[i].rawScore/no_of_question)); printf("\n"); printf("\nsummary REPORT:\n"); printf(" Question no. percent correct number correct \n"); for (i=0; i<no_of_question; i++) for (j=0; j<no_of_student; j++) if (solution[i]==examtakers[j].answers[i]) correct++; printf("%10s%3d%22.2f%25d\n","quest. ", i+1, 100*((float)correct/no_of_student), correct); correct=0; printf("for all %d students :\n", no_of_student);

10 printf(" the average score = %7.2f\n", statistics[0]); printf(" the standard deviation = %7.2f\n", statistics[1]); printf(" the median = %7.2f\n", statistics[2]); printf("for each of the %d questions :\n", no_of_question); printf(" the average = %7.2f\n", statistics[3]); printf(" the standard deviation = %7.2f\n", statistics[4]); printf(" the median = %7.2f\n", statistics[5]);

Flowchart, Types, and Values

Flowchart, Types, and Values Course Number CLO : 1 Week : 1-3 : FEH1H3 CLO#1 Student have the knowledge to create algorithm and iteration Know the fundamental of computer system Understand the components