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

A. a>b? c = 20 : c = 21;

B. a>b? c = 20;

C. max = a>b? a>c?a:c:b>c?b:c;

D. return (a>b)?(a:b);

A. True

B.  False

A. / + * –

B. * – / +

C. + – / *

D. / * + –

A. * / % + – =

B. = * / % + –

C. / * % – + =

D.  * % / – + =

#include<stdio.h>
#include<conio.h>
 
int main()
{
    int i = 4, j = -1, k = 0, w, x, y, z;
    w = i||j||k;
    x = i&&j&&k;
    y = i||j&&k;
    z = i&&j||k;
    printf("%d  %d  %d  %d", w, x, y, z);
    getch();
}

A. 1 1 1 1

B. 1 0 0 1

C. 1 0 1 1

D. Other

#include <stdio.h>
#include <conio.h>
 
void main()
{
    static int a[20];
    int i = 0;
    a[i] = i;
    printf("%d  %d  %d", a[0], a[1], i);
    getch();
} 

A. 1 0 1

B. 1 1 1

C. 0 0 0

D. 0 1 0

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int x = 12, y = 7, z = 2;
    z = x != 4 || y == 2;
    printf("z = %d", z);
    getch();
}

A. z = 0

B. z = 1

C. z = 4

D. z = 3

A.  Yes

B. No

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 3, j = 2, k = -1, m;
    m = ++i||++j&&++k;
    printf("%d  %d  %d  %d", i, j, k, m);
    getch();
}

A. 4 2 -1 1

B. 4 3 0 1

C. 3 2 -1 1

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 3, j = 2, k = -1, m;
    m = ++i&&++j&&++k;
    printf("%d  %d  %d  %d", i, j, k, m);
    getch();
}

A. 4 3 0 0

B. 3 3 0 1

C. 4 2 0 0

D. None of these

a <= 20 ? (b = 30) : (c = 30);
(a <= 20) ? b : (c = 30);

A. Yes

B. No

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 2;
    int j = i + (1, 2, 3, 4);
    printf("j = %d", j);
    getch();
}

A. 6

B. 3

C. 12

D. Complier error

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

A. 0 4 1

B. 1 4 1

C.  4 4 1

D. None of these

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int n = 2;
    printf("%d  %d", ++n, ++n);
    getch();
}

A. 4 4

B. 3 4

C. 2 2

D. 2 3

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int a = 10, b = 19;
    int c;
    c = (a == 10 || b < 20);
    printf("c = %d", c);
    getch();
}

A. c = 1

B. c = 29

C. c = 10

D. c = 19

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int x = 4, y, z;
    y = --x;
    z = x--;
    printf("%d %d %d", x, y, z);
    getch();
}

A. 4 3 2

B. 4 3 3

C. 2 3 2

D. 2 3 3

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int k, num = 20;
    k = (num>5 ? (num <= 10 ? 10 : 30): 40);
    printf("%d", k);
    getch();
}

A. 20

B. 30

C. 40

D. 10

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

A. 4

B. 3

C. Complier error

D. None of above

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int arr[3] = {3};
    int i;
    for(i = 0; i <= 2; i++)
    printf("%d, ", arr[i]);
    getch();
}

A. 3, 0, 0,

B. 3, 3, 3,

C. 3, garbage, garbage

D. Another

float func()
{    
    int r = 0, d = 0, i = 0;    
    for (i; i < 2; i++)     
    {        
        r += 5 / d;    
    }       
    return r;
}

A. 5

B. 0

C. Exception

D. Another

void main()
{
    char s[] = "man"; 
    int i; 
    for(i = 0; s[i]; i++) 
        printf("%c%c%c%c\t", s[i], *(s+i), *(i+s), i[s]); 
    getch();
}

A. mmmm aaaa nnnn

B.  mmm aaa nnn

C. mmmm aaa nnn

D. Another

void main()
{
     int i = 0;
     char ch = 'A';
     do
     {
         putchar(ch);
     }
     while(i++ < 5 || ++ch <= 'F');
     getch();
}

A. AAAAAABCDEF

B. AAAAAABCDE

C. ABCDEF

D. Another

void main()
{
    int array[2][2] = {0, 1, 2, 3};
    int i;
    int sum = 0;
    for (i = 0; i < 4; ++i)
    {
        int x, y;
        x = i % 2;
        if (x)
        {
            y = 0;
        }
        else
        {
            y = 1;
        }
        sum += array[x][y];
    }
    printf("%d\n", sum);
    getch();
}

A. 3

B. 4

C. 5

D. 6

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int k;
    for (k = -3; k < -5; k++)
        printf("Hello");
    getch();
}

A. Hello

B. Nothing

C. Complier Error

D. Run time error

void main()
{
    double k = 0;
    for (k = 0.0; k < 3.0; k++);
    printf("%lf", k);
    getch();
}

A. 012

B.  Run time error

C. 3

D. 2

#include <stdio.h>
int main()
{
    int i = 0;
    for (; ; ; )
        printf("In for loop\n");
    printf("After loop\n");
}

A. Complie time error

B. Infinite Loop

C. Nothing

#include <conio.h>
#include <stdio.h>
int foo();
void main()
{
    int i = 0;
    for (foo(); i == 1; i = 2)
        printf("In for loop\n");
    printf("After loop\n");
    getch();
}
int foo()
{
    return 1;
}

A. In for loop

B. After loop

C. Complie error

#include <conio.h>
#include <stdio.h>
 
int main()
{
    int i = 0;
    while (i = 0)
        printf("True\n");
    printf("False\n");
    getch();
}

A. True

B.  False

C. Complie Error

D. Another

#include <conio.h>
#include <stdio.h>
int main()
{
    int i = 0, j = 0;
    while (i < 5, j < 10)
    {
        i++;
        j++;
    }
    printf("%d, %d\n", i, j);
    getch();
}

A. 5, 5

B. 10, 10

C. Syntax error

#include <conio.h>
#include <stdio.h>
 
int main()
{
    int a = 0, i = 0, b = 0 ;
    for (i = 0; i < 5; i++)
    {
        a++;
        continue;
        b++;
    }
    printf("\n a = %d,b =%d", a, b);
    getch();
}

A. a = 5,b = 5

B. a = 4,b = 4

C. a = 5,b = 0

D. Another

void main()
{
    int i = 0;
    for (i = 0; i < 5; i++)
    if (i < 4)
    {
        printf("Hello");
        break;
    }
    getch();
}

A.  Hello

B. Hello is printed 3 times

C. Hello is prined 4 times

D. Hello is printed 5 times

#include <stdio.h>
#include <conio.h>
void main()
{
    int i = 0;
    for(; i <= 2; )
        printf(" %d", ++i);
    getch();
}

A. 1 2 3

B. 0 1 2 3

C. 0 1 2

#include <stdio.h>
#include <conio.h>
void main()
{
    int x;
    for(x = 1; x <= 5; x++);
        printf("%d", x);
    getch();
}

A. 12345

B. 123456

C. 6

D. 1234

#include <stdio.h>
#include <conio.h>
int main()
{
    int i = 3;
    while (i--)
    {
        int i = 100;
        i--;
        printf("%d ", i);
    }
    getch();
}

A. 99 99 99

B. Complier Error

C. 1

#include <stdio.h>
#include <conio.h>
 
int main()
{
    int i = 1024;
    for (; i; i >>= 1)
        printf("\nlaptrinhc++");
    getch();
}

A. 10

B. 11

C. Infinite

#include <stdio.h>
#include <conio.h>
void main()
{
    int i = 2, j = 2;
    while(i+1? --i : j++)
       printf("%d", i);
    getch();
}

A. 1

B. 2

C. Complier Error

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i, j;
    i = j = 2;
    while(--i&&j++)
        printf("%d %d", i, j);
    getch();
}

A. 1 3

B. 1 2

C. Không in ra kí tự nào

#include <stdio.h>
#include <conio.h>
 
int main()
{
    int x = 011, i;
    for(i = 0; i < x; i += 3)
    {
        printf("Start ");
        continue;
        printf("End");
    }
    getch();
}

A. Start End Start End

B. Start Start Start

C. Start Start Start Start

#include <stdio.h>
#include <conio.h>
 
void main() 
{
    int s = 0;
    while (s++ < 10) 
    {
        if (s < 4 && s < 9)
            continue;
        printf(" %d ", s);
    }
    getch();
}

A. 1 2 3 4 5 6 7 8 9

B. 3 4 5 6 7 8 9

C. 4 5 6 7 8 9

D. 4 5 6 7 8 9 10

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i = 6;
    while(i)
    {
        if (i > 5)
        {
            i--;
        }
        i = i + 5;
        if (i > 34)
        {
            break;
        }
    }
    printf("%d", i);
    getch();
}

A. Infinite loop

B. 35

C. 38

D. 39

#include <stdio.h>
#include <conio.h>
 
int print(int i);
 
void main()
{
    int i = 6;
    while(print(i) || --i);
    getch();
}
 
int print(int i)
{
    printf("%d, ", i);
    return 0;
}

A. 6, 5, 4, 3, 2, 1,

B. 6, 5, 4, 3, 2, 1, 0,

C. Complier Error

D. Infinite loop

#include <stdio.h>
#include <conio.h>
 
int func(int* i);
 
void main()
{
    int i = 15;
    while(func(&i) && i++ > 0);
    printf("%d", i);
    getch();
}
 
int func(int* i)
{
    *i -= 5; 
    return(*i);
}

A. 0

B. -1

C. -2

D. -3

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

A. 0

B. 2

C. 3

D. -4

#include <stdio.h>
#include <conio.h>
 
void main()
{
    int i, j;
    for(i = 0, j = 0; i < 5, j < 6; i++, j++)
    {
        printf("i = %d \t j = %d\n", i, j);
    }
    getch();
}

A.  print i and j from 0 till 4

B. print i and j from 0 till 5

C. print i from 0 to 4, print j from 0 to 5

D. Complier Error

void main()
{
    int i = 3;
    if (!i)
       i++;
    i++;
 
    if (i == 3)
    i += 2;
    i += 2;
    printf("%d\n", i);
    getch();
}

A. 5

B. 6

C. 7

D. Another

void main()
{
    int x;
    if(x = 0)
        printf ("Value of x is 0");
    else
        printf ("Value of x is not 0");
    getch();
}

A. Value of x is 0

B. Value of x is not 0

C. Error

void main()
{
    int i;
    for(i = 0; i < 20; i++)
    {
        switch(i)
        {
        case 0:i+=5;
        case 1:i+=2;
        case 5:i+=5;
        default: i+=4;
        break;
        }
        printf("%d,", i);
    }
    getch();
}

A. 14,18,

B. 16,20,

C. 16,21,

void main()
{
    static int i;
    while(i <= 10&&i >= 0)
        (i > 2 ? i++ : i--);
    printf("%d", i);
    getch();
}

A. -1

B. 0

C. 1

D. Complier error

void main()
{
    int i = 10, j = 20;
    if(i = 20)
        printf(" Hello");
    else
        printf(" Hi");
 getch();
}

A. Hello

B. Hi

C. Complier error

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

A. x=0 y=1

B. x=0 y=0

C. Error syntax