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C Questions

C Questions Page 1(New)

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C Problems
  1. What will print out?

main()
{
        char
*p1=“name”;
        char
*p2;
        p2=(char*)malloc(20);
        memset (p2, 0, 20);
        while(*p2++ = *p1++);
        printf
(“%s\n”,p2);

}

Answer:empty string.

  1. What will be printed as the result of the operation below:

main()
{
    int
x=20,y=35;
    x=y++ + x++;
    y= ++y + ++x;
    printf
(“%d%d\n”,x,y);

}

Answer : 5794

  1. What will be printed as the result of the operation below:

main()
{
    int x=5;
    printf(“%d,%d,%d\n”,x,x< <2,x>>2);

}

Answer: 5,20,1

  1. What will be printed as the result of the operation below:

#define swap(a,b) a=a+b;b=a-b;a=a-b;

void main()
{
    int x=5, y=10;
    swap (x,y);
    printf(“%d %d\n”,x,y);
    swap2(x,y);
    printf(“%d %d\n”,x,y);
}

int swap2(int a, int b)
{
    int temp;
    temp=a;
    b=a;
    a=temp;
    return 0;

}

Answer: 10, 5
10, 5

  1. What will be printed as the result of the operation below:

main()
{
    char *ptr = ” Cisco Systems”;
    *ptr++; printf(“%s\n”,ptr);
    ptr++;
    printf(“%s\n”,ptr);

}

Answer:Cisco Systems
isco systems

  1. What will be printed as the result of the operation below:

main()
{
    char s1[]=“Cisco”;
    char s2[]= “systems”;
    printf(“%s”,s1);
}

Answer: Cisco

  1. What will be printed as the result of the operation below:

main()
{
    char *p1;
    char *p2;

    p1=(char *)malloc(25);
    p2=(char *)malloc(25);

    strcpy(p1,”Cisco”);
    strcpy(p2,“systems”);
    strcat(p1,p2);

    printf(“%s”,p1);

}

Answer: Ciscosystems

  1. The following variable is available in file1.c, who can access it?:
9.static int average;

Answer: all the functions in the file1.c can access the variable.

  1. WHat will be the result of the following code?

#define TRUE 0 // some code

while(TRUE)
{

    // some code

}

Answer: This will not go into the loop as TRUE is defined as 0.

  1. What will be printed as the result of the operation below:

int x;
int modifyvalue()
{
    return(x+=10);
}

int changevalue(int x)
{
    return(x+=1);
}

void main()
{
    int x=10;
    x++;
    changevalue(x);
    x++;
    modifyvalue();
    printf("First output:%d\n",x);

    x++;
    changevalue(x);
    printf("Second output:%d\n",x);
    modifyvalue();
    printf("Third output:%d\n",x);

}

Answer: 12 , 13 , 13

  1. What will be printed as the result of the operation below:

main()
{
    int x=10, y=15;
    x = x++;
    y = ++y;
    printf(“%d %d\n”,x,y);

}

Answer: 11, 16

  1. What will be printed as the result of the operation below:

main()
{
    int a=0;
    if(a==0)
        printf(“Cisco Systems\n”);
        printf(“Cisco Systems\n”);

}

Answer: Two lines with “Cisco Systems” will be printed.