400 Câu hỏi trắc nghiệm lập trình C/C++ có đáp án và lời giải chi tiết

A. Yes

B. No

A. Yes

B. No

A. Yes

B. No

#include<stdio.h>
 
void main()
{
    int a;
    a = f(1, 3.14);
}
 
float f(int a, float b)
{
    return ((float)a + b);
}

A. Add prototype: float f(int, float);

B. Add prototype: float f(a, b);

C. Add prototype: float f(float a, int b)

A. Yes

B. No

#include <stdio.h>
#include <conio.h>
 
void main()
{
    printf("%p", main());
    getch();
}

A. It prints garbage values infinitely

B. Runs infinitely without printing anything

C. Error: main( ) cannot be called inside printf( )

D. No Error and print nothing

int f1(int a, int b)
{
    return(f2(20));
}
 
int f2(int a)
{
    return a*a;
}

A. Yes

B. No

A. Yes

B. No

A. Yes

B. No

#include <stdio.h>
#include <conio.h>
 
int reverse(int);
 
void main()
{
    int n = 5;
    reverse(n);
    getch();
}
 
int reverse(int n)
{
    if(n == 0)
        return 0;
    else
        printf("%d", n);
    reverse(n--);
}

A. 543210

B. 54321

C. 12345

D. Infinite loop

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int func(int);
    int i = func(5);
    printf("%d", --i);
    getch();
}
 
int func(int n)
{
    return(n++);
}

A. 4

B. 5

C. 6

D. Another

f(int a, int b)
{
    int a;
    a = 20;
    return a;
}

A. Missing parenthesis in return statement

B. The function should be defined as int f(int a, int b)

C. Re-declaration of a

D. None of above

#include <stdio.h>
#include <conio.h>
 
int f(int a)
{
    a > 20 ? return(1) : return(0);
}
 
void main()
{
    int f(int);
    int b = f(20);
    printf("%d", b);
    getch();
}

A. Error: Prototype declaration

B. No error

C. Error: return statement cannot be used with conditional operators

D. None of above

#include<stdio.h>
#include <conio.h>
 
int func(int i, int j)
{
    int k, l;
    k = i + j;
    l = i * j;
    return (k, l);
}
 
void main()
{
    int i = 2, j = 3, k, l;
    k = func(i, j);
    l = func(i, j);
    printf("%d  %d", k, l);
    getch();
}

A. 6 6

B. 5 6

C. Complier error

D. None of above

#include<stdio.h>
#include <conio.h>
 
int f1(int);
int f2(int);
 
void main()
{
    extern int i;
    int j = 3;
    f1(j);
    printf("%d,", j);
    f2(j);
    printf("%d", j);
    getch();
}
 
int f1(int i)
{
    printf("%d,",++i);
    return 0;
}
int f2(int j)
{
    printf("%d,", ++j);
    return 0;
}

A. 4, 3, 4, 3

B. 4, 4, 5, 5

C. 3, 4, 3, 4

D. None of above

long fun(int n)
{
    int i;
    long f = 1;
    for(i = 1; i <= n; i++)
        f = f*i;
    return f;
}

A. The function calculates the value of 1 raised to power n

B. The function calculates the factorial value of an integer

C.  The function calculates the square root of an integer

D. None of above

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int a = 10;
    void f();
    a = f();
    printf("%d", a);
    getch();
}
 
void f()
{
    printf("vncoding");
}

A. Error: cannot convert ‘void’ to ‘int’

B.  Error:

#include <stdio.h>
#include <conio.h>
 
int main()
{
    printf("%d\t", sizeof(6.5));
    printf("%d\t", sizeof(90000));
    printf("%d", sizeof('A'));
    getch();
}

A. 8 4 1

B. 8 2 1

C. 4 4 1

D.  Depend on complier

#include <stdio.h>
 
int main()
{
    double num = 5.2;
    int var = 5;
    printf("%d\t", sizeof(!num));
    printf("%d\t", sizeof(var=15/2));
    printf("%d", var);
    return 0;
}

A. 1 4 5

B. 1 4 7

C. 8 4 7

D. Another

#include <stdio.h>
 
int main()
{
    int w = 3;
    int x = 31;
    int y = 10;
    double z = x / y % w;
    printf("%f\n", z);
 
    return 0;
}

A. 1

B. 0

C. 0.1

#include <stdio.h>
 
int main()
{
    char a = 250;
    int expr;
    expr= a + !a + ~a + ++a;
    printf("%d", expr);
    return 0;
}

A. -6

B. 5

C. 4

D. Another

#include <stdio.h>
 
int main()
{
    int a = -5;
    unsigned int b = -5u; // (*)
    if(a == b)
        printf("Avatar");
    else
        printf("Alien");
    return 0;
}

A. Avatar

B. Alien

C.  Error at (*)

D. Another

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int x = 3;
    printf("%d", x++ + ++x);
    getch();
}

A. 7

B. 8

C. 9

D. Another

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 5, j = 6, k;
    k = i & j;
    printf("%d", k);
    getch();
}

A. 4

B. 0

C. 1

D. 5

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 5,j = 6;
    printf("%d", i | j); 
    getch();
}

A. 7

B. 6

C. 5

D. 1

#include <stdio.h>
#include <conio.h>
 
extern int x = 0; 
 
void main()
{
    x++;
    printf("%d", x); 
    getch();
}

A. 0

B. Error

C. 1

D. x isn’t defined

#include <stdio.h>
#include <conio.h>
 
extern int x = 0;
 
void main()
{
    {
        int x = 1;
    }
    printf("%d", x);
    getch();
}

A. 0

B. 1

C. Error Comlier

#include <stdio.h>
#include <conio.h>
 
int y = 0;
void main()
{
    {
        int x = 0;
        x++;
        ++y;
    }
    printf("%d\t%d", x, y);
    getch();
}

A. 1 1

B. 1 0

C.  ‘x’ undeclared identifier

void main()
{
    int x;
    {
        x++;
    }
    printf("%d", x);
    getch();
}

A. 1

B. 0

C. Error

void main()
{
    int x=0;
    {
        int x = 0, y = 0;
        y++;
        x++;
    }
    printf("%d", x);
    getch();
}

A. 1

B. Error

C. 0

void count()
{
    static int page = 0;
    printf("%d", page);
    page++;
}
 
void main()
{
    int i;
    for(i = 0; i < 10; i++)
    {
        count();
    }
    getch();
}

A. 0123456789

B. 0000000000

C. 0101010101

const int x = 5;
 
void main()
{
    int x[x];
    int y = sizeof(x) / sizeof(int);
    printf("%d", y);
    getch();
}

A. 1

B. 5

C. 20

D. ‘x’ isn’t defined

#include <stdio.h>
 
int main()
{
    int x = 5, y = 10, z = 15;
    printf("%d %d %d");
    return 0;
}

A. Garbage Garbage Garbage

B. 5 10 15

C. 15 10 5

D. Run time error

#include <stdio.h>
 
int main()
{
    char *url="c:\tc\bin\rw.c";
    printf("%s", url);
    return 0;
}

A. c:/tc/bin/rw.c

B. c: c inw.c

C.  c:cinw.c

D.  w.c in

#include <stdio.h>
 
int main()
{
    const int i = 5;
    i++;
    printf("%d", i);
    return 0;
}

A. 5

B. 6

C. 0

D. Complier error

#include <stdio.h>
#include <conio.h>
 
void main()
{
    char c = 125;
    c = c + 10;
    printf("%d", c);
    getch();
}

A. 135

B. 8

C. -121

D. 121

#include <stdio.h>
#include <conio.h>
 
int main()
{
    char c = 48;
    int i, mask = 01;
    for(i = 1; i <= 5; i++)
    {
        printf("%c", c|mask);
        mask = mask << 1;
    }
    getch();
}

A.  12480

B. 1248@

C. 12500

D. 12522

#include <stdio.h>
#include <conio.h>
 
int main()
{
    float a = 0.7;
    if(0.7 > a)
        printf("Hi\n");
    else
        printf("Hello\n");
    getch();
}

A. Hi

B. Hello

C. None of above

#include <stdio.h>
#include <conio.h>
void main()
{
    int x = 10, y = 20, z = 5, i;
    i = x < y < z;
    printf("i = %d", i);
    getch();
}

A. i = 0

B.  i = 1

C. Error

D. None of these

A.  int length;

B. char int;

C.  int long;

D. float double;

#include <stdio.h>
#include <conio.h>
 
int N = 10;
void main()
{
    int N = 20;
    printf("N = %d", N);
    getch();
}

A. N = 20

B. N = 10

C. Error

D. No Output

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int a[5] = {1, 2};
    printf("%d %d %d", a[2], a[3], a[4]);
    getch();
}

A. 0 0 0

B. 1 2 2

C. 1 1 1

D. Error

#include <stdio.h>
#include <conio.h>
 
void main()
{
    extern int func(float);
    int a;
    a = func(3.14);
    printf("%d", a);
    getch();
}
 
int func(float a)
{
    return (int)++a;
}

A. 3

B. 4

C. Complier Error

D. 3.14

A.  int i = 35; i = i%5

B. short int j = 5; j = j;

C. long int k = 123L; k = k;

D. float a = 3.14; a = a%3;

#include <stdio.h>
#include <conio.h>
 
void main()
{
    void v = 0;
    printf("%d", v);
    getch();
}

A. Error: Declaration syntax error v (or) ‘v’: illegal use of type ‘void’

B.  Program terminate abnormally

C. No error

D. None of these

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 5;
    for(;scanf("%d", &i); printf("%d", i));
    getch();
}

A. The for loop would not get executed at all

B. The for loop would get executed only once

C.  The for loop would get executed 5 times

D. The for loop would get executed infinite times

#include <stdio.h>
#include <conio.h>
 
void main()
{
    display();   
    getch();
}
 
void display()
{
    printf("vncoding.net");
}

A. No error

B. display( ) is not declared

C. None of these

A. 1, 2

B. 1, 3

C. 2, 4

D. 1, 2, 3

A. True

B. False

a = f1(11, 16) * f2(12/8)  +  f3();

A. f1, f2, f3

B. f3, f2, f1

C. Order may vary from complier to complier

D. None of above