(English version. There is also a Swedish version of this exam.)

• Write clearly. Solutions that can't be read can't give any points. Vague and ambiguous wording will be misinterpreted.
• Write the personal exam code on each sheet submitted. Do not write your name or person number on the sheets.
• Write only on one side of the paper. Do not use red writing.
• Assumptions in addition to those in the problems must be stated.
• You can write explanations of your reasoning. Even an answer that is wrong may give credit, if there is an explanation that shows that the main ideas were right.

Precedence and associativity of operators in C

Some useful library functions

stdlib.h

       int rand(void);
       void srand(unsigned int seed);
       void *malloc(size_t size);
       void *realloc(void *ptr, size_t size);
       void free(void *ptr);
       void exit(int status);
       void qsort(void *base, size_t nmemb, size_t size,
                  int(*compar)(const void *, const void *));

stdio.h

       FILE *fopen(const char *path, const char *mode);
       int fclose(FILE *stream);
       int getc(FILE *stream);
       int getchar(void);
       int ungetc(int c, FILE *stream);
       char *fgets(char *s, int size, FILE *stream);
       char *gets(char *s);
       int putc(int c, FILE *stream);
       int printf(const char *format, ...);
       int fprintf(FILE *stream, const char *format, ...);
       int sprintf(char *str, const char *format, ...);
       int snprintf(char *str, size_t size, const char *format, ...);
       int scanf(const char *format, ...);
       int fscanf(FILE *stream, const char *format, ...);
       int sscanf(const char *str, const char *format, ...);
       size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
       size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);

string.h

       size_t strlen(const char *s);
       char *strcpy(char *dest, const char *src);
       char *strncpy(char *dest, const char *src, size_t n);
       int strcmp(const char *s1, const char *s2);
       int strncmp(const char *s1, const char *s2, size_t n);
       char *strcat(char *dest, const char *src);
       char *strncat(char *dest, const char *src, size_t n);
       char *strstr(const char *haystack, const char *needle);
       void *memmove(void *dest, const void *src, size_t n);

ctype.h

       int isalnum(int c);
       int isalpha(int c);
       int isblank(int c);
       int isdigit(int c);
       int islower(int c);
       int isprint(int c);
       int ispunct(int c);
       int isspace(int c);
       int isupper(int c);

Task 1 (1 p)

a) 4 * 3 − 2 + 1

b) 4 − 3*2 + 1

c) 4 / 3 − 4 / 2

Task 2 (3 p)

#include <stdio.h>

int g(int x, int y) {
    int i, a, b, c;
    a = 17;
    b = 2;
    c = 38;
    for (i = x; i < y; i++)
        printf("*");
    return x + y;
}

int main(void) {
    int a;
    int b, c;
    for (a = 1; a < 3; ++a) {
        b = a + 1;
        c = g(a, b);
        printf("a = %d, b = %d, c = %d\n", a, b, c);
    }
    return 0;
}

Task 3 (3 p)

Scenario

struct Triangle {
    double a, b, c;
};

a, b and c are the lengths of the sides of the triangle. The sides can be stored in any order, so there is for example no guarantee that the triangle's longest side is anyone specific of a, b or c. All lengths must be greater than zero.

Task 4 (1 p)

Task 5 (2 p)

void show_triangle(struct Triangle t)

or like this:

void show_triangle(struct Triangle *tp)

Task 6 (3 p)

struct Triangle read_triangle(void)

or like this:

void read_triangle(struct Triangle* tp)

Task 7 (5 p)

Write the functions min and max.

Task 8 (2 p)

Task 9 (3 p)

Task 10 (4 p)

• reads data into the variable using the function read_triangle
• prints the triangle using show_triangle
• calculates tha area of the triangle using area, and prints it
• asks for and lets the user input a scaling factor
• applies that scaling factor on the triangle using the function scale
• prints the re-scaled triangle using show_triangle
• calculates tha area of the re-scaled triangle using area, and prints it

Task 11 (3 p)

Task 12 (3 p)

For realistic testing we would need more than just one call, but here we only do one. Thus there is only a single test case. Try to make that test case as good as possible!

Task 13 (3 p)

If the file can not be opened, an error message should be printed, and the program should be terminated.

Do not forget to specify if you chose a text file or a binary file!

Task 14 (3 p)

If the file can not be opened, an error message should be printed, and the program should be terminated.

Task 15 (1 p)

#include <stdio.h>

int main(void) {
    double x = 0.2, y = 6.0, z = 1.2;
    printf("%f\n", x * y);
    printf("%f\n", z);
    if (x * y == z)
        printf("Lika, förstås.\n");
    else
        printf("Va? Inte lika!\n");
    return 0;
}