Programming Essentials in C: Mock Test (CLA) Exam Answers

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1. What is the value of the following integer literal?

17
15
23
the literal is invalid

2. What is the value of the following integer literal?

0x17

15
17
the literal is invalid
23

3. Which of the following strings is a valid variable name?

none of these
anti_world
anti:world
anti-world

4. Which of the following declarations is valid?

float float;
float int;
float long;
float floating;

5. What is the value of the X variable at the end of the following snippet?

    int X = 8;
    X = X - X / 2;
    X = X * X / 4;
    X = X + 2 * X;

6. What is the value of the X variable at the end of the following snippet?

    float X = 2.0;
    X = X + X * 4;
    X = X / X * X;
    X = X / X + X;

11.000000
0.500000
1.000000
110.000000

7. Which of the following strings is a proper floating-point number (in the “C” language sense)?

3E8
3,0×10^8
300,000,000
3.0×10^8

8. What is the value of the Y variable at the end of the following snippet?

    int X = 1, Y = X + 2, Z = Y++;

    Z = X / Y * --X * Y--;

9. What is the value of the X variable at the end of the following snippet?

    int X;

    X = ('r' - 's') * ('A' / 'Z');

1
the snippet is invalid and will cause a compilation error
2
0

10. What happens if you try to compile and run this program?

    #include <stdio.h>
    int main(void) {
        int x = 1, y = 1;
        float k = -1e0, m = 2e1;
        printf("%d\n", (x >= y) + (x >= y) + (k >= y) + (m >= k) + ('q' <= 'z'));
        return 0;
    }

the program outputs 4
the program outputs 1
the program outputs 3
the program outputs 2

11. What happens if you try to compile and run this program?

    #include <stdio.h>
    int main(void) {
        int i = 1;
        if(i = 0)
        	i = 2;
        else
        	i = 3;
        printf("%d\n",i);
        return 0;
    }

the program outputs 4
the program outputs 2
the program outputs 1
the program outputs 3

12. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = 1, j = 0;
        do {
        	i *= 2;
        	j += i / 2;
        } while(j < 1);
        printf("%d",i + j); 
        return 0; 
    }

the program outputs 3
the program outputs 1
the program enters an infinite loop and does not output anything
the program outputs 2

13. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = 5, j = 16;
        while(j >= 0) {
        	i /= 2;
        	j -= i / 2;
        } 
        printf("%d",i + j); 
        return 0; 
    }

the program enters an infinite loop and does not output anything
the program outputs 1
the program outputs 3
the program outputs 2

14. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = 1, j;
        for(j = 0; j ; j--) 
        	i *= 2;
        printf("%d",i + j); 
        return 0; 
    }

the program outputs 1
the program enters an infinite loop and does not output anything
the program outputs 2
the program outputs 3

15. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = -1, j = 1;
        for(i++; i++; i++) 
        	j++;
        printf("%d",i + j); 
        return 0; 
    }

the program outputs 3
the program enters an infinite loop and does not output anything
the program outputs 1
the program outputs 2

16. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = 1, j = 0, k;
        k = (i >> j) + (j >> i) + (i >> i) + (j >> j);
        k <<= i;
        printf("%d", k); 
        return 0; 
    }

the program outputs 0
the program outputs 1
the program outputs 4
the program outputs 2

17. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = 3, j = i - 2 * i;
        switch(i - j) {
        	case  1: j++;
        	case  2: j--;
        	case  0: j++; break;
        	default: j = 0;
        }
        printf("%d", ++j); 
        return 0; 
    }

the program outputs 1
the program outputs 4
the program outputs 2
the program outputs 0

18. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i = 5, j = i - 4 * i;
        switch(j) {
        	default: j = 2;
        	case  1: j--; break;
        	case  2: j++;
        	case  0: j--; break;
        }
        printf("%d", j++); 
        return 0; 
    }

the program outputs 4
the program outputs 0
the program outputs 2
the program outputs 1

19. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i, t[4];
        for(i = 0; i < 3; i++) {
        	t[i] = 4 - i;
        	t[i + 1] = 2 * t[i];
        }
        printf("%d\n", t[2]);
        return 0; 
    }

the program outputs 1
the program outputs 4
the program outputs 0
the program outputs 2

20. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        int i, s = 0, t[] = {16, 8, 4, 2, 1, 0};
        for(i = 5; t[i] > 2; i /= 2) 
        	s += t[i];
        printf("%d\n", s);
        return 0; 
    }

the program outputs 0
the program outputs 4
the program outputs 2
the program outputs 1

21. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        char t[] = { 'x', 'z', 'Y', 'Z', '2' , '0'};
        printf("%d\n", t[t[1] - t[0] - t[3] + t[2] + 3] - t[5]);
        return 0; 
    }

the program outputs 0
the program outputs 2
the program outputs 4
the program outputs 1

22. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        float a = 3.14E0, *b = &a, **c = &b;
        **c = a + (a == *b);
        printf("%f", a);
        return 0; 
    }

the program outputs 4.140000
the program outputs NULL
the program outputs 2.140000
the program outputs 3.140000

23. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        char t[4][4];
        printf("%d\n",sizeof(t) / sizeof(t[0]) / sizeof(t[0][0]));
        return 0; 
    }

the program outputs 8
the program outputs 1
the program outputs 2
the program outputs 4

24. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        char *p = "\0\2\1\3\4";
        printf("%d\n", p[p[2]] + *(p + 1) + p[0]);
        return 0; 
    }

the program outputs 8
the program outputs 1
the program outputs 4
the program outputs 2

25. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #include <string.h>
    int main(void) { 
        char tt[20] = "9081726354";
        strcpy(tt, tt + 3);
        printf("%d\n", strlen(tt) - tt[9] + '5');
        return 0; 
    }

the program outputs 8
the program outputs 1
the program outputs 2
the program outputs 4

26. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #include <string.h>
    int main(void) { 
        char tt[20] = "0123456789";
        strcat(tt + 11, "123");
        printf("%d\n", strlen(tt) - tt[8] + '0');
        return 0; 
    }

the program outputs 2
the program outputs 1
the program outputs 8
the program outputs 4

27. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #include <stdlib.h>
    int main(void) { 
        float *t = 1 + (float *) malloc(sizeof(float) * sizeof(float));
        t--;
        *t = 8.0;
        t[1] = *t / 4.0;
        t++;
        t[-1] = *t / 2.0;
        printf("%f\n",*t);
        free(--t);
        return 0; 
    }

the program outputs 1.000000
the program outputs 8.000000
the program outputs 4.000000
the program outputs 2.000000

28. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #include <string.h>
    struct S {
        char S[8];
    };
    int main(void) { 
        struct S S = { 'a', 'b', 'c', 'd' };
        printf("%d", sizeof(S.S) - strlen(S.S) + S.S[4]); 
        return 0; 
    }

the program outputs 4
the program outputs 8
the program outputs 1
the program outputs 2

29. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #include <string.h>
    #include <stdlib.h>
    struct S {
        char *S;
    };

    int main(void) { 
        struct S *S = (struct S *) malloc(sizeof(struct S));
        S -> S = "123\0""45678";
        printf("%d", strlen(S -> S + 5) + S -> S[3]); 
        free(S);
        return 0; 
    }

the program outputs 2
the program outputs 8
the program outputs 4
the program outputs 1

30. What happens if you try to compile and run this program?

    #include <stdio.h> 
    struct S {
        int Var;
        struct S *Str;
    };
    int main(void) { 
        struct S S[] = { { 8, NULL }, { 4, &S[0] }, { 2, &S[1] } };
        printf("%d", S[2].Str->Str->Var);
        return 0; 
    }

the program outputs 1
the program outputs 2
the program outputs 4
the program outputs 8

31. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int fun(int *t) {
        return *(t + 3);
    }
    int main(void) { 
        int arr[] = { 3, 2, 1, 0 };
        printf("%d\n", fun(arr - 2));
        return 0; 
    }

the program outputs 1
the program outputs 2
the program outputs 8
the program outputs 4

31. What happens if you try to compile and run this program?

    #include <stdio.h> 
    float f(float v) { 
        	v = v / 2.0;
        return v + v;
    } 
    int main(void) { 
        float x = 4; 
        f(x); 
        printf("%f",x); 
        return 0; 
    }

the program outputs 8.000000
the program outputs 1.000000
the program outputs 4.000000
the program outputs 2.000000

32. What happens if you try to compile and run this program?

    #include <stdio.h> 
    char *f(char *p) { 
        return p += 2;
    } 
    char *g(char *p) {
        return --p;
    }
    int main(void) { 
        char *s = "ABCDEFGHIJ";
        char  p = *f(g(f(s + 1)));
        printf("%d",p - 'A'); 
        return 0; 
    }

the program outputs 1
the program outputs 2
the program outputs 8
the program outputs 4

33. What happens if you try to compile and run this program?

    #include <stdio.h> 
    struct S {
        int S[3];
    };
    void f(struct S S) { 
        S.S[0] = S.S[1] + S.S[2] - 4;
    } 
    int main(void) { 
        struct S S = { { 1, 4, 2 } };
        f(S);
        printf("%d",S.S[1] * S.S[0]); 
        return 0; 
    }

the program outputs 8
the program outputs 1
the program outputs 2
the program outputs 4

34. What happens if you try to compile and run this program?

    #include <stdio.h> 
    struct S {
        int S[3];
    };
    void f(struct S *S) { 
        S->S[2] = 6 * S->S[0] + S -> S[1];
    } 
    int main(void) { 
        struct S S = { { 1, 2 } }, *P = &S;
        f(P);
        printf("%d",S.S[2] / S.S[0]); 
        return 0; 
    }

the program outputs 2
the program outputs 1
the program outputs 4
the program outputs 8

35. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #include <string.h>
    char *f(int p, char *s) { 
        s[p + 2] = '\0';
        return s - 1;
    } 
    int main(void) { 
        char s[] = "ABCDEF";
        int i = strlen(f(1,s + 2));
        printf("%d\n",i); 
        return 0; 
    }

the program outputs 4
the program outputs 8
the program outputs 1
the program outputs 2

36. What happens if you try to compile and run this program?

    #include <stdio.h> 
    int main(void) { 
        char s[20] = "?"; 
        FILE *f = fopen("fopen","w"); 
        int i = fputs("789",f); 
        fclose(f); 
        f = fopen("fopen","r"); 
        fgets(s + 1,3,f); 
        printf("%c\n", s[2] - s[3]); 
        fclose(f); 
        return 0; 
    }

the program outputs 1
the program outputs 8
the program outputs 4
the program outputs 2

37. What happens if you try to compile and run this program?

    #include <stdio.h> 
    #define  ONE    1
    #define  TWO 	ONE + ONE
    int main(void) { 
        int i = 2;
        i = i - 2 * TWO;
        printf("%d\n", i);
        return 0; 
    }

the program outputs 4
the program outputs 2
the program outputs 1
the program outputs 0

38. What is the meaning of the following declaration?

    float *f(int);

f is a pointer to function (int) returning float;
f is a function (int) returning pointer to float;
f is a pointer to function (float) returning int;
the declaration is incorrect

39. Select the proper form for the following declaration:
ptr is a pointer to pointer to pointer to double

double **ptr;
double ***ptr;
double *ptr;
the declaration is invalid and cannot be coded in C