Thread: c programing help

Please read and follow the homework policy.

This problem is quite simple . . .

Assuming you're working a maximum size of, say, 32. (unsigned long int, in other words)


(yes, I *know* that long is the same thing as int on most modern systems.)

Code:

char *convert_to_binary(unsigned long number) {
    unsigned long bitmasks[32] = {0x01};
    int x;
    char *result = malloc(sizeof(char) * 33);
    for(x = 1; x < 32; x ++) {
        bitmasks[x] = bitmasks[x-1] * 2;
    }
    for(x = 0; x < 32; x ++) {
        result[x] = (number & bitmasks[x])?'1':'0';
    }
    return result;
}

Not that there is insufficient error checking etc. in there.

Also, I haven't tried it, so I'm not 100% certain if it'll work, but that should work.

Code:

there is one error in your code ---  type mismatch in redeclaration of checkpaliendrome

#include<conio.h>
#include<stdio.h>
#include<math.h>
void paliendrome(int a,int b)
{
int m;
for (i=a;i<=b;i++)
{
m=convertdecimaltobinary(i);//converts the decimal no to it s binary equivalent
checkpaliendrome(m);//checks whether the binary no is a paliendrome or not
}
}
int  convertdecimaltobinary(int x)
 {
    unsigned long bitmasks[32] = {0x01};
    int x;
    char *result = malloc(sizeof(char) * 33);
    for(x = 1; x < 32; x ++) {
        bitmasks[x] = bitmasks[x-1] * 2;
    }
    for(x = 0; x < 32; x ++) {
        result[x] = (number & bitmasks[x])?'1':'0';
    }
    return result;
}

void checkpaliendrome(int y)
{
int k=y,new=0;
int r=y;
int u,v,c=0;//c counts the number of digits 
while(k>0)
{
u=k%10;
k=k/10;
c=c+1;
}
while (r>0)
{
u=r%10;
v=pow(10,c-1)*u ;
new=new+v;
c--;
}
if (new ==y)
{ printf("%d",y);
}
}

//both decimal and binary equivalents have to be paliendromes

void main()
{
int t,u,l;
scanf("%d",&t);
int i ;
//t stands for the no of cases
for(i=0;i<=t;i++)
{
scanf("upperrange",&u);
scanf("lowerrange",&l);
paliendrome(u,l);
}


please tell me how will correct it

i have added indentetion to the code and some questions in the comments

Code:

//conio.h is not standard
#include<conio.h>
#include<stdio.h>
#include<math.h>

void paliendrome(int a,int b)
{
	int m;
	for (i=a;i<=b;i++)
	{
		m=convertdecimaltobinary(i);//converts the decimal no to it s binary equivalent
		checkpaliendrome(m);//checks whether the binary no is a paliendrome or not
	}
}
int  convertdecimaltobinary(int x)
{
	unsigned long bitmasks[32] = {0x01};
	int x; /* this local var hides the past parameter */
	/* do you see the type of result? */
	char *result = malloc(sizeof(char) * 33);
	for(x = 1; x < 32; x ++) {
		bitmasks[x] = bitmasks[x-1] * 2; /* what do you think this is doing? */
	}
	for(x = 0; x < 32; x ++) {
		result[x] = (number & bitmasks[x])?'1':'0';
	}
	return result; /* you trying to return char* while return type is int */
}
/* are you checking binary or decimal palindrom? */
void checkpaliendrome(int y)
{
	int k=y,new=0;
	int r=y;
	int u,v,c=0;//c counts the number of digits 
	while(k>0)
	{
		u=k%10;
		k=k/10;
		c=c+1;
	}
	while (r>0)
	{
		u=r%10;
		v=pow(10,c-1)*u ;
		new=new+v;
		c--;
	}
	if (new ==y)
	{ printf("%d",y);
	}
}

//both decimal and binary equivalents have to be paliendromes

/* main should be int main(void) - read FAQ */
void main()
{
	int t,u,l;
	scanf("%d",&t);
	int i ;
	//t stands for the no of cases
	for(i=0;i<=t;i++)
	{
		scanf("upperrange",&u); /* you have no format specifier here */
		scanf("lowerrange",&l);
		paliendrome(u,l); 
	}
}