[C] 큰 자리수의 덧셈

addBigNum.c

#include <stdio.h>
#include <stdlib.h>

void str_rev(char *s);
void ltrim(char *s, char c);
void rtrim(char *s, char c);
void ljust(char *dest, char *source, int length, char c);
void rjust(char *dest, char *source, int length, char c);
char * stradd(char *s1, char *s2);

int main(void)
{
	char *s1 = "1234543547356756874546562523453457456785678567858456256464567";
	char *s2 = "2432565356756756785678354634563456567567856788788563456345612";
	char *s = stradd(s1,s2);
	printf("%s\n", s);
	free(s);
	return 0;
}


void rtrim(char *s, char c)
{
	str_rev(s);
	ltrim(s,c);
	str_rev(s);
}

void rjust(char *dest, char *source, int length, char c){
	if(length==0 || length == NULL){length = strlen(dest);}
	int i=0, l=strlen(source);
	for(i=0;i<length;i++)
	{
		if(i<length-l) {dest[i] = c; }
		else {dest[i] = source[i-(length-l)]; }
	}
}

void str_rev(char *s)
{
	char temp;
	int i, len = strlen(s);
	for(i=0;i<len/2;i++)
	{
		temp = *(s+i);
		*(s+i) = *(s+len-1-i);
		*(s+len-i-1) = temp;
	}
}

void ltrim(char *s, char c)
{
	int i=0,l=strlen(s);
	while(i<l && s[i]==c)
	{
		i++;
	}
	if(i!=0) {
		int j=0;
		while(j<l-i)
		{
			s[j] = s[j+i];
			j++;
		}
		s[l-i]=0;
	}
}

void ljust(char *dest, char *source, int length, char c){
	if(length == 0 || length == NULL) {length = strlen(dest); }
	int i;
	for(i=0;i<length;i++)
	{
		if(i<strlen(source)) {dest[i] = source[i]; }
		else {dest[i] = c; }
	}
}

char * stradd(char *s1, char *s2){
	int maxLen = (strlen(s1)>=strlen(s2) ? strlen(s1) : strlen(s2)) + 1;
	char *a1 = (char*)calloc(sizeof(char), maxLen+1);
	char *a2 = (char*)calloc(sizeof(char), maxLen+1);
	char *result = (char*)calloc(sizeof(char), maxLen+1);
	rjust(a1, s1, maxLen, '0');
	rjust(a2, s2, maxLen, '0');
	str_rev(a1);
	str_rev(a2);
	int i;
	char v=0, temp=0;
	for(i=0;i<maxLen;i++)
	{
		v = (a1[i]-48) + (a2[i]-48) + temp;
		if(v>9){temp=1; v = v % 10;}
		else{temp=0;}
		result[i] = v+48;
	}
	result[maxLen] = 0;
	str_rev(result);
	ltrim(result,'0');
	free(a1); free(a2);
	return result;
}

E015.m

#import <Foundation/Foundation.h>

NSString *mutipliyStrings(NSString *str1, NSString *str2);
NSString *stringWithReversedArray(NSArray *reversedArray);
NSString *ltrim(NSString *str, unichar ch);
NSString *rjust(NSString *str, NSUInteger length, unichar ch);
NSString *addStrings(NSString *str1, NSString *str2);
NSString *factorial(NSString *str);

NSString *rjust(NSString *str, NSUInteger length, unichar ch)
{
	unichar *prefix = (unichar *)malloc((length - [str length]) * sizeof(unichar));
	NSUInteger i=0;
	while(i<(length - [str length])) {
		*(prefix+i) = ch;
		i++;
	}
	*(prefix+i) = 0;
	NSString *result = [NSString stringWithFormat:@"%S%@", prefix, str];
	free(prefix);
	return result;
}

NSString *ltrim(NSString *str, unichar ch)
{
	NSUInteger i = 0;
	while(i < [str length] && [str characterAtIndex:i] == ch ) i++;
	return [str substringFromIndex:i];
}

NSString *stringWithReversedArray(NSArray *reversedArray)
{
	NSUInteger i;
	unichar *string = (unichar *)calloc([reversedArray count] , sizeof(unichar));
	for(i=0;i<[reversedArray count];i++) {
		*(string+i) = (unichar)([[reversedArray objectAtIndex:([reversedArray count]-i-1)] charValue] + 48);
	}
	// printf("%s\n", string);
	NSString *result = [NSString stringWithCharacters:string length:[reversedArray count]];
	free(string);
	return result;
}


NSString *addStrings(NSString *str1, NSString *str2)
{
	NSUInteger len = ([str1 length] > [str2 length]) ? [str1 length]+1 : [str2 length]+1;
	NSString *v1 = rjust(str1, len, '0');
	NSString *v2 = rjust(str2, len, '0');
	NSMutableArray *reversed = [NSMutableArray array];
	int i;
	int a,b,k=0,temp;;
	for(i=len;i>0;i--) {
		a = [v1 characterAtIndex:i-1] - 48;
		b = [v2 characterAtIndex:i-1] - 48;
		temp = a+b+k;
		if(temp > 9) {
			k = 1;
			temp = temp - 10;
		}else{
			k=0;
		}
		[reversed addObject:@(temp)];
	}
	return ltrim(stringWithReversedArray(reversed), '0');
}

NSString *mutipliyStrings(NSString *str1, NSString *str2)
{
	NSMutableArray *rows = [NSMutableArray array];
	NSMutableArray *reversedRow = [NSMutableArray array];
	NSUInteger rowIndex, colIndex;
	int a,b,c,temp=0;
	for(rowIndex=[str1 length];rowIndex > 0;rowIndex--) {
		[reversedRow removeAllObjects];
		int k;
		for(k=0;k<[str1 length]-rowIndex;k++) {
			[reversedRow addObject:@(0)];
		}
		a = [str1 characterAtIndex:rowIndex-1] - 48;
		for(colIndex=[str2 length];colIndex>0;colIndex--) {
			b = [str2 characterAtIndex:colIndex-1] - 48;
			c = a*b+temp;
			if(c > 9) {
				temp = (c / 10);
				c = c - temp*10;
			} else {
				temp = 0;
			}
			[reversedRow addObject:@(c)];
		}
		if(temp) {
			if(temp > 9) {
				[reversedRow addObject:@(floor(temp % 10))];
				[reversedRow addObject:@(floor(temp/10))];
			}
			else {
				[reversedRow addObject:@(temp)];
			}
		}
		// NSLog(@"%@", reversedRow);
		[rows addObject:ltrim(stringWithReversedArray(reversedRow),'0')];
	}
	NSString *allSum = @"0";
	for(NSString *row in rows) {
		// NSLog(@"%@",row);
		allSum = addStrings(row, allSum);
	}
	[rows removeAllObjects];
	return allSum;
}

NSString *factorial(NSString *str)
{
	int k = [str intValue];
	NSString *f = [@"1" retain];
	while(k>1) {
			NSString *kstring = [NSString stringWithFormat:@"%d", k];
			NSLog(@"%@ X %@",f, kstring);
			f = mutipliyStrings(f, kstring);
			k--;	
	}
	return f;
}



int main(int argc, char const *argv[])
{
	@autoreleasepool {
		// NSLog(@"%@", mutipliyStrings(@"361829371852383189442705860000", @"85"));
		NSLog(@"%@", factorial(@"100"));
	}
	return 0;
}

calloc의 사용법을 잘 못 알고 있었다.

char *str = (char*)calloc(sizeof(char), stringLength+1);

과 같이 써야 하며, 이 때 할당되는 메모리 크기는 두 인자의 곱이다.