lab6.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>

//USING C98 standard

const float PI = 3.14;

int my_abs(int x) {
    if (x >= 0) return x;
    else return -x;
}

float my_circle_area(float r) {
    return PI * r * r;
}


float my_cylinder_volume(float r, float h) {
    return h * my_circle_area(r);
}

void lower_to_upper(char* s) {
    for (int i = strlen(s) - 1; i >= 0; i--)
        s[i] = toupper(s[i]);
    return;
}

void change(char* s) {
    for (int i = strlen(s) - 1; i >= 0; i--)
        switch(s[i]) {
            case 'A': case 'a':
            case 'B': case 'b':
            case 'C': case 'c':
                s[i] = 'X';
                break;
            case 'D': case 'd':
            case 'E': case 'e':
            case 'F': case 'f':
                s[i] = 'Y';
                break;
        }
    return;
}

long fac(int n) {
    if (n <= 1) return 1;
    return n * fac(n - 1);
}

int main()
{
    // tests

    assert(my_abs(-6) == 6);
    assert(my_abs(6) == 6);
    assert(my_abs(0) == 0);

    assert(fac(0) == 1);
    assert(fac(1) == 1);
    assert(fac(2) == 2);
    assert(fac(3) == 6);
    assert(fac(4) == 24);

    assert(my_circle_area(0) == 0);
    assert(my_circle_area(-1) == PI);
    assert(my_circle_area(1) == PI);
    assert(my_circle_area(2) == 4 * PI);

    assert(my_cylinder_volume(0, 0) == 0);
    assert(my_cylinder_volume(1, 2) == 2 * PI);
    assert(my_cylinder_volume(2, 2) == 8 * PI);

    char s1[] = "";
    lower_to_upper(s1);
    assert(strcmp(s1, "") == 0);
    char s2[] = "ASDFasdf";
    lower_to_upper(s2);
    assert(strcmp(s2, "ASDFASDF") == 0);

    char s3[] = "";
    change(s3);
    assert(strcmp(s3, "") == 0);
    char s4[] = "ASDFasdf";
    change(s4);
    assert(strcmp(s4, "XSYYXsYY") == 0);

    printf("All tests executed\n");
    return 0;
}