Conversion Between String and Number

◀ Pause For Some Time▶ Tokenize a String Amazon The header <stdlib.h> provides the following functions for number conversion:

• double atof(const char *s): converts s to double
• int atoi(const char *s): converts s to int
• long atol(const char *s): converts s to long

Note that all the above functions have the common property that if the given string contains characters other than numbers, they still return some value; they don’t crash. They also work with negative values. Conversions to string from double, int, and long may need to be written by you.

The following function, dtoa(), converts a double or int to a string. It also works with negative values.

int getnod(int a){
	int t=1;
	while((a/=10)!=0)
		t++;
	return t;
}
bool allZeros(string s){
	for(int i=0; i<s.length(); i++)
		if(s[i]!='0')
			return false;
	return true;
}
string dtoa(double val){
	char *buffer;
	string bufs;
	int precision = 6;
	int decimal, sign, i;

	buffer = fcvt(val, precision, &decimal, &sign);
	bufs+=buffer;

	if(decimal<=0){
		bufs.insert(0,"0.");
		for(i=0;i>decimal;i--)
			bufs.insert(2,"0");
	}
	else{
		if(allZeros(bufs.substr(getnod((int)val))))
			bufs=bufs.substr(0,getnod((int)val));
		else
			bufs.insert(getnod((int)val),".");
	}
	if(sign==0)
		return bufs;
	return "-"+bufs;
}

◀ Pause For Some Time▶ Tokenize a String