C Essentials – Final Test

C Essentials – Final Test

  1. What is the value of the x variable at the end of the following snippet?

    int x = 1;

x = x + 2 * x;
x = x / 2 * x;
x = x + 2 + x;
    • 1
    • 8
    • 4
    • 2

  2. Which of the following declarations is valid?

    • int long;
    • int int;
    • int float;
    • int longint;

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

    #include <stdio.h>
int mian(void) {
    int t[4] = {0, -1, -2, -3}, *p = t + 3;

    printf("%d\n", p[*p] - t[2]);
    return 0;
}
    • the program outputs 1
    • the program outputs 8
    • the program outputs 4
    • the program outputs 2

  4. 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->Var);
    return 0;
}
    • the program outputs 8
    • the program outputs 1
    • the program outputs 2
    • the program outputs 4

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

    #include <stdio.h>
int main(void) {
    int i = 16, j = 8;
    do {
         i /= 2;
         j = i / 2;
    }while(j > 0);
          printf("%d", i + j);
    return 0;
}
    • the program enters an infinite loop and outputs nothing
    • the program outputs 4
    • the program outputs 1
    • the program outputs 2

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

    #include <stdio.h>
#define ABC 10
#define XYZ ABC - 1

int main(void) {
    int i = 19;
    i = i - XYZ;

    printf("%d\n", i);
    return 0;
}
    • the program outputs 4
    • the program outputs 1
    • the program outputs 8
    • the program outputs 2

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

    #include <stdio.h>

int main(void) {
    char *t1 [10];
    char *t2 [10];

    printf("%d", (sizeof(t1) == sizeof(t2)) + sizeof(t1[0]));
    return 0;
}
    • the program outputs 1
    • the program outputs 4
    • the program outputs 2
    • the program outputs 8

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

    #include <stdio.h>

int main(void) {
    char s[20];
    FILE *f = fopen("data", "w");
    int i = fputs("1248", f);
    fclose(f);
    f = fopen("data", "r");
    fgets(s + 2, 4, f);
    putchar(s[4]);
    fclose(f);
    return 0;
}
    • the program outputs 8
    • the program outputs 2
    • the program outputs 4
    • the program outputs 1

  9. What is the value of the following floating-point literal?

    -1E-1
    • -0.1
    • -1.0
    • -0.01
    • the literal is valid

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

    #include <stdio.h>

int main(void) {
    int i = 5, j = 4;
    for(i--; i--; i--)
        j--;
    printf("%d", i + j);
    return 0;
}
    • the program outputs 1
    • the program enters an infinite loop and outputs nothing
    • the program outputs 4
    • the program outputs 2

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

    #include <stdio.h>

int main(void) {
    int i, s = 0, t[] = {0, 1, 2, 4, 8, 16};
  
    for(i = 2; t[i] < 8; i *= 2) 
        s += t[i];
        
         printf("%d\n", s);
     return 0;
}
    • the program outputs 0
    • the program outputs 2
    • the program outputs 4
    • the program outputs 1

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

    #include <stdio.h>

int fun(int *t) {
    return * (++t);
}

int main(void) {
    int arr[] = {8, 4, 2, 1};

    printf("%d\n", fun(arr + 2));
    return 0;
}
    • the program outputs 1
    • the program outputs 1
    • the program outputs 4
    • the program outputs 8

  13. Which of the following string is a legal variable name?

    • Alpha_Omega
    • Alpha:Omega
    • Alpha@Omega
    • Alpha-Omega

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

    #include <stdio.h>

int main(void) {
    int t[4][4];

    printf("%d\n", sizeof(t) / sizeof(t[0]) / sizeof(t[0][0]));
    return 0;
}
    • the program outputs 2
    • the program outputs 1
    • the program outputs 4
    • the program outputs 8

  15. 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 = "abc";

    printf("%d", strlen(S -> S + 2) + S -> S[3]);
    free(S);
    return 0;
}
    • the program outputs 1
    • the program outputs 2
    • the program outputs 8
    • the program outputs 4

  16. What is the meaning of the following declaration?

    void (*f) (int);
    • f is a pointer to function (int) returning int;
    • f is a function  (int)returning pointer to  void;
    • f is a pointer to function (int) returning void;
    • the declaration is erronous

  17. Which of the following is are legal variable names?

    • 2R2D
    • R2D2
    • _R2D2_
    • _2R2D_

  18. What is the value of the x variable at the end of the following snippet?

    int x = 1;

x = x * x + 2;
x = x / x * 2;
x = x + 2 + x;
    • 2
    • 8
    • 6
    • 4

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

    0x12
    • 10
    • 18
    • the literal is invalid
    • 12

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

    #include <stdio.h>

struct S{
      int S[2];
};

void f(struct S *S) {
    S -> S[1] = S -> S[0] + 2;
}

int main(void) {
    struct S S = {{4, 8}}, *p = &S;
    f(P);
    printf ("%d", S.S[1] / S.S[0]);
    return 0;
}
    • the program outputs 8
    • the program outputs 4
    • the program outputs 1
    • the program outputs 2

  21. Select the proper form for the following declaration:

    ptr is a pointer to pointer to void

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

  22. 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 4
    • the program outputs 1
    • the program outputs 2

  23. What is the value of the x variable at the end of the following snippet?

    int x;
x = 'b' - 'a' * ('\' / '\');
    •  2
    • 0
    • 1
    • the snippet is invalid and will cause compilation error

  24. What is the value of the x variable at the end of the following snippet?

    int x = 1, y = 2, z;
z = x / y * --x * y++;
    • 1
    • 0
    • 4
    • 2

  25. What is the value of the x variable at the end of the following snippet?

    #include <stdio.h>
int main(void) {
    int i = 1, j = 0, k;

        k = (i & j) + (i | j) + (i ^ j) + !i + j;
        
        printf("%d", k);
     return 0;
}
    • the program outputs 1
    • the program outputs 2
    • the program outputs 4
    • the program outputs 0

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

    012
    • 18
    • the literal is invalid
    • 10
    • 12

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

    #include <stdio.h>

int f(int v) {
      v = 2 * v;
    return v * v;
}

int main(void) {
    int i = 2;
    f(i);

    printf("%d", i);
    return 0;
}
    • the program outputs 8
    • the program outputs 2
    • the program outputs 4
    • the program outputs 1

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

    #include <stdio.h>

int main(void) {
    int i = 16, j = 6;
    while(j > 0) {
       i /= 2;
       j -= i / 2;
    }
        printf("%d", i + j);
    return 0;
}
    • the program enters an infinite loop and outputs nothing
    • the program outputs 4
    • the program outputs 1
    • the program outputs 2

  29. 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] = i;
       t[i + 1] = 2 * t[i];
    }
       printf("%d\n", t[3]);
    return 0;
}
    • the program outputs 0
    • the program outputs 2
    • the program outputs 1
    • the program outputs 4

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

    • 3.1415M92
    • 3.1415F92
    • 3.1415X92
    • 3.1415E92

  31. 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 + 2, "987");

    printf("%d\n", strlen(tt) - tt[5] + '0');
    return 0;
}
    • the program outputs 1
    • the program outputs 8
    • the program outputs 4
    • the program outputs 2

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

    #include <stdio.h>
#include <string.h>

int main(void) {
    char tt[20] = "0123456789";
    strcpy(tt, tt + 2);

    printf("%d\n", strlen(tt) - tt[9] + '5');
    return 0;
}
    • the program outputs 1
    • the program outputs 2
    • the program outputs 4
    • the program outputs 8

  33. 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 + 1] = '\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 1
    • the program outputs 8
    • the program outputs 2
    • the program outputs 4

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

    #include <stdio.h>

int main(void) {
    int i = 2, j;

        for(j = 0; j < 0; j -= i)
        i /= 2;

        printf("%d", i + j);
     return 0;
}
    • the program enters an infinite loop and outputs nothing
    • the program outputs 1
    • the program outputs 4
    • the program outputs 2

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

    #include <stdio.h>

int main(void) {
    int i, t[4];

    for(i = 3; i; i--) {
        t[i] = i - 1;
        t[t[i]] = t[i];
    }
        printf("%d\n", t[0]);
    return 0;
}
    • the program outputs 2
    • the program outputs 4
    • the program outputs 0
    • the program outputs 1

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

    #include <stdio.h>

int main(void) {
    int i = 1, j = i + 2 * i;
    switch(j) {
         default: j = 0;
         case 1: j++; break;
         case 2: j--;
         case 0: j++; break;
    }
         printf("%d", ++j);
     return 0;
}
    • the program outputs 0
    • the program outputs 1
    • the program outputs 2
    • the program outputs 4

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

    #include <stdio.h>

struct S {
       int S[2];
};

void f(struct S S) {
      S.S[0] = S.S[1] + 4;
}
int main(void) {
    struct S S = {{4, 8}};
    f(S);

    printf("%d", S.S[1] / S.S[0]);
    return 0;
}
    • the program outputs 4
    • the program outputs 1
    • the program outputs 8
    • the program outputs 2

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

    #include <stdio.h>
int main(void) {
    int i = 0;
    if(i = 1)
       i = 2;
    else
       i = 3;
       printf("%d\n", i);
    return 0;
}
    • the program outputs 1
    • the program outputs 3
    • the program outputs 4
    • the program outputs 2

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

    #include <stdio.h>

char *f(char *p) {
     return p++;
}
char *g(char *p){
     return p += 2;
}

int main(void) {
    char *s = "ABCDEFGHIJ";
    char p = *f(g(f(s + 6)));

    printf("%d", p - 'A');
    return 0;
}
    • the program outputs 4
    • the program outputs 1
    • the program outputs 8
    • the program outputs 2

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

    #include <stdio.h>
int main(void) {
    int a = -1, b = 1;
    float i = 2.0, j = -2.0;

    printf("%d\n", (a > b) + (b > a) + (i > j) + (j > i) + ('z' > 'a'));
    return 0;
}
    • the program outputs 2
    • the program outputs 1
    • the program outputs 3
    • the program outputs 4

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

    #include <stdio.h>

int main(void) {
    float x = 3.0, y = 2.0;
    int i = 1, j = 2;
    x = (int)x / y + (float)i / j;

    printf("%f", x);
    return 0;
}
    • the program outputs2.000000
    • the program outputs 3.000000
    • the program outputs 0.000000
    • the program outputs 1.000000

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

    #include <stdio.h>

int f(int t[][2]) {
     return t[0][0] + t[0][1];
}
int main(void) {
    int i, t[2][2] = {{0,4}, {4,2}};
    i = f(t);

    printf("%d", i);
    return 0;
}
    • the program outputs 1
    • the program outputs 2
    • the program outputs 8
    • the program outputs 4

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

    #include <stdio.h>

int main(void) {
    char *p = "\0\4\1\3\2";

    printf("%d\n", p[p[1]] + *(p + 1) + p[4]);
    return 0;
}
    • the program outputs 1
    • the program outputs 8
    • the program outputs 2
    • the program outputs 4

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

    #include <stdio.h>

int main(void) {
    int i = 1, j = i + 2 * i;

    switch(j - i) {
          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

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

    #include <stdio.h>

int fun(int t) {
     return ++t;
}

int main(void) {
    int arr[] = {8, 4, 2, 1};

    printf("%d\n", fun(arr[3]) + arr[2]);
    return 0;
}
    • the program outputs 1
    • the program outputs 2
    • the program outputs 4
    • the program outputs 8

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

    #include <stdio.h>

int main(void) {
    char t[] = {'a', 'z', 'B', 'Z', '0'};

    printf("%d\n", t[t[1] - t[0] - t[3] + t[2] + 3] - t[4]);
    return 0;
}
    • the program outputs 4
    • the program outputs 2
    • the program outputs 0
    • the program outputs 1

  47. Which of the following is a valid integer number (in the “C” language sense)?

    • 3_141_592
    • 3.141592
    • 3141592
    • 3,141592

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

    #include <stdio.h>
#include <string.h>

struct S {
     char S[4];
};

int main(void) {
    struct S S = {'a', 'b'};

    printf("%d", sizeof(S.S) - strlen(S.S) + S.S[3]);
    return 0;
}
    • the program outputs 4
    • the program outputs 8
    • the program outputs 2
    • the program outputs 1

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

    #include <stdio.h>
#include <stdlib.h>

int main(void) {
    int *t = (int *) malloc(sizeof(int) + sizeof(int));
    t++;
    *t = 8;
    t[ 1] = *t / 2;
    t--;
    t[1] = *t / 2;

    printf("%d\n", *t);
    free(t);
    return 0;
}
    • the program outputs 2
    • the program outputs 1
    • the program outputs 8
    • the program outputs 4

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

    #include <stdio.h>

int main(void) {
    char a = 'A', *b = &a, **c = &b;
    **c = a + (a == *b);

    printf("%c", a);
    return 0;
}
    • the program outputs C
    • the program outputs NULL
    • the program outputs B
    • the program outputs A