6.15大数加法（十进制和十六进制）

#include <stdio.h>
#include <string.h>


void Swap(char &a,char &b)
{
	char t = a;
	a =b;
	b = t;
}
void ReverseString(char *s)
{
	int i=0;
	int j= strlen(s)-1;
	while (i<j)
	{
		Swap(s[i],s[j]); 
		i++; j--;
	}
}

void Add(char *A,char *B,char *C)
{
	char AA[200]; char BB[200];
	strcpy(AA,A);
	ReverseString(AA); 
	strcpy(BB,B);
	ReverseString(BB);
	int carry =0 ;
	int lenA = strlen(AA);
	int lenB = strlen(BB);
	int lenZ=0;
	int i=0;
	for (i=0; i<lenA && i<lenB ; ++i)
	{
		int tmp = carry+AA[i]-'0'+BB[i]-'0';
		carry = tmp/10;
		C[lenZ++] = tmp%10+'0';
		
	}
	while (i<lenA)
	{
		int tmp = carry+AA[i]-'0';
		carry = tmp/10;
		C[lenZ++] = tmp%10 +'0';
		++i;
	}
	while (i<lenB)
	{
		int tmp = carry+BB[i]-'0';
		carry = tmp/10;
		C[lenZ++] = tmp%10 +'0';
		++i;
	}
	if(carry)
	{
		C[lenZ++] = carry+'0';
	}
	while (C[lenZ-1]=='0')
	{
		lenZ--;
	}
	C[lenZ]=0;
	ReverseString(C);

}

int main()
{
	char A[200];
	char B[200];
	char C[201];

	char S[400];
	scanf("%s",S);

	int pos ;
	int lenS =strlen(S);
	for (int i=0;i<lenS;++i)    //查找加号
	{
		if(S[i]=='+') 
		{
			pos=i;
			break;
		}
	}


	int i;
	for (i=0;i<pos;++i)            //前面复制给A
	{
		A[i]=S[i];
	}
	A[i]=0;
	
	for (i=pos+1;i<lenS;++i)          //后面复制给B
	{
		B[i-pos-1]=S[i];
	}
	B[lenS-pos-1]=0;



	//strcpy(A,"1234");
	//strcpy(B,"23456");
	Add(A,B,C);
	printf("%s\n",C);

	return 0;

}

#include <stdio.h>
#include <string.h>


void Swap(char &a,char &b)
{
	char t = a;
	a =b;
	b = t;
}
void ReverseString(char *s)
{
	int i=0;
	int j= strlen(s)-1;
	while (i<j)
	{
		Swap(s[i],s[j]); 
		i++; j--;
	}
}

void Add(char *A,char *B,char *C)
{
	char AA[200]; char BB[200];
	strcpy(AA,A);
	ReverseString(AA); 
	strcpy(BB,B);
	ReverseString(BB);
	int carry =0 ;
	int lenA = strlen(AA);
	int lenB = strlen(BB);
	int lenZ=0;
	int i=0;
	for (i=0; i<lenA && i<lenB ; ++i)
	{
		int tmp = carry;
		if (AA[i]>='A' && AA[i]<='F')
		{
			tmp+= (AA[i]-'A'+10);
		} 
		else
		{
			tmp+= (AA[i]-'0');
		}
		if (BB[i]>='A' && BB[i]<='F')
		{
			tmp+= (BB[i]-'A'+10);
		} 
		else
		{
			tmp+= (BB[i]-'0');
		}
			
		carry = tmp/16;
		tmp = tmp%16;
		if (tmp<10)
		{
			C[lenZ++] = tmp+'0';
		} 
		else
		{
			C[lenZ++] = tmp-10+'A';
		}
		

	}
	while (i<lenA)
	{
		int tmp = carry;
		if (AA[i]>='A' && AA[i]<='F')
		{
			tmp+= (AA[i]-'A'+10);
		} 
		else
		{
			tmp+= (AA[i]-'0');
		}
		carry = tmp/16;
		
		tmp = tmp%16;
		if (tmp<10)
		{
			C[lenZ++] = tmp+'0';
		} 
		else
		{
			C[lenZ++] = tmp-10+'A';
		}

		++i;
	}
	while (i<lenB)
	{
		int tmp = carry;
		if (BB[i]>='A' && BB[i]<='F')
		{
			tmp+= (BB[i]-'A'+10);
		} 
		else
		{
			tmp+= (BB[i]-'0');
		}
		carry = tmp/16;
		tmp = tmp%16;
		if (tmp<10)
		{
			C[lenZ++] = tmp+'0';
		} 
		else
		{
			C[lenZ++] = tmp-10+'A';
		}
		++i;
	}
	if(carry)
	{
		if (carry<10)
		{
			C[lenZ++] = carry+'0';
		} 
		else
		{
			C[lenZ++] = carry-10+'A';
		}
	}
	while (C[lenZ-1]=='0')
	{
		lenZ--;
	}
	C[lenZ]=0;
	ReverseString(C);

}

int main()
{
	char A[200];
	char B[200];
	char C[201];

	strcpy(A,"0000000001");
	strcpy(B,"FFFFFFFFFFFF");
	Add(A,B,C);
	printf("%s\n",C);

}