两个大数的加、减、乘、除、取余

#include<stdio.h>#include<string.h>#include<stdlib.h>char *add_together(char *a,char *b);//两数相加char *subtract(char *a,char *b);//两数相减char *divide(char *a,char *b,int d);//两数相除char *multiplied(char *a,char *b);//两数相乘bool contrast(char *a,char *b,int c);//检查a,b两个字符串的大小void inspect_char_valid(char *a,char *b);//检查两个字符串是否有其他符号void printf_char(char *a);//输出字符串int main(){char a[1000],b[1000],c;do{printf("请输入一个数：");gets(a);printf("请输入一个数：");gets(b);printf("请输入'+','-','*','/','%%'的任意一个符号：");c=getchar();switch (c){case '+':printf("两数相加的结果是:");printf_char(add_together(a,b));break;case '-':printf("两数相减的结果是:");printf_char(subtract(a,b));break;case '*':printf("两数相乘的结果是:");printf_char(multiplied(a,b));break;case '/':printf("两数相除的结果是:");printf_char(divide(a,b,20));break;case '%':divide(a,b,0);printf("第一个数对第二个数取余的结果是:");printf_char(a);break;default:printf("你输入的不是'+','-','*','/','%'其中的符号\n退出！！！\n");}getchar();}while (c=='+' || c=='-' || c=='*' || c=='/' || c=='%');return 0;}char *add_together(char *a,char *b)//两数相加{inspect_char_valid(a,b);int i,j,c_len,sum,Carry=0;char c[1000]={'\0'};if (strlen(a)>strlen(b))c_len=(int)strlen(a);elsec_len=(int)strlen(b);for (i=0;i<c_len;i++){sum=Carry;if (((int)strlen(a)-i)>0)sum=sum+a[strlen(a)-1-i]-'0';if (((int)strlen(b)-i)>0)sum=sum+b[strlen(b)-1-i]-'0';if (sum<10){c[c_len-1-i]=sum+'0';Carry=0;}else{c[c_len-1-i]=(sum%10)+'0';Carry=sum/10;}}if(Carry){for (j=strlen(c);j>0;j--){c[j]=c[j-1];}c[0]=Carry+'0';Carry=0;}return c;}char *subtract(char *a,char *b)//两数相减{inspect_char_valid(a,b);char c[1000]={'\0'};int i,j,a_len,b_len,h,sum,borrow=0;for (i=0;*(a+i)=='0';i++);for (j=0;*(b+j)=='0';j++);a_len=(int)strlen(a);b_len=(int)strlen(b);if ((a_len-i)<(b_len-j)||((a_len-i)==(b_len-j)&&contrast(b,a,1))) {c[0]='-';strcpy(c+1,b);for (h=0;h<b_len;h++){if ((a_len-h)>0)if ((b[b_len-1-h]+borrow)>=a[a_len-1-h]){c[b_len-h-j]=b[b_len-1-h]+borrow-(a[a_len-1-h]-'0');borrow=0;}else{c[b_len-h-j]=b[b_len-1-h]+borrow+10-(a[a_len-1-h]-'0');borrow=-1;}else{if ((borrow+c[b_len-h-j]-'0')<0){c[b_len-h-j]=c[b_len-h-j]+10+borrow;borrow=-1;}else{c[b_len-h-j]=c[b_len-h-j]+borrow;borrow=0;}}}}else{strcpy(c,a);for (h=0;h<a_len;h++){if ((b_len-h)>0)if ((a[a_len-1-h]+borrow)>=b[b_len-1-h]){c[a_len-1-h]=a[a_len-1-h]+borrow-(b[b_len-1-h]-'0');borrow=0;}else{c[a_len-1-h]=a[a_len-1-h]+borrow+10-(b[b_len-1-h]-'0');borrow=-1;}else{if ((borrow+c[a_len-h-1]-'0')<0){c[a_len-h-1]=c[a_len-h-1]+10+borrow;borrow=-1;}else{c[a_len-h-1]=c[a_len-h-1]+borrow;borrow=0;}}}}return c;}char *divide(char *a,char *b,int d=0)//两数相除{inspect_char_valid(a,b);char bb[10][1000]={'\0'},c[1000]={'\0'},tihuan;int i,j,h=0,a_len,b_len;a_len=(int)strlen(a);b_len=(int)strlen(b);for (i=1,strcpy(bb[0],b);i<10;i++)strcpy(bb[i],add_together(bb[i-1],b));i=0;if (a_len>=b_len){for (i=0;i<=a_len-b_len;a[b_len+i]=tihuan,i++){tihuan=a[b_len+i];a[b_len+i]='\0';for (j=0;j<10 && contrast(a,bb[j],0);j++);if (j){strcpy(a,subtract(a,bb[j-1]));}a[b_len+i]=tihuan;c[i]=j+'0';}}for (c[i]='.',h=1;h<=d;h++){a[a_len+h-1]='0';a[a_len+h]='\0';for (j=0;j<10 && contrast(a,bb[j],0);j++);if (j){strcpy(a,subtract(a,bb[j-1]));}c[i+h]=j+'0';}return c;}char *multiplied(char *a,char *b)//两数相乘{inspect_char_valid(a,b);char c[1400][1400]={'\0'};long long Product,Carry=0;int i,j,r,k,k1=0;k=strlen(a);i=strlen(b);//这里是计算b里面的每一个数字与a大数相乘的结果，并放在c数组相应的位子---- for (i=i-1;i-k1>=0;k1++){for (r=k1,c[i-k1][k+r]='\0';r>0;r--){c[i-k1][k+r-1]='0';}for (j=k-1;j>=0;j--){Product=Carry+(b[i-k1]-'0')*(a[j]-'0');if (Product<10){c[i-k1][j]=Product+'0';Carry=0;}else{c[i-k1][j]=(Product%10)+'0';Carry=Product/10;}}//这里是检查每个数与大数相乘结束后，最后是否还需要进位------------------ if (Carry){for (j=k+k1,c[i-k1][j+1]='\0';j>0;j--){c[i-k1][j]=c[i-k1][j-1];}c[i-k1][0]=Carry+'0';Carry=0;}}//下面是把c数组里面的大数从后面对其相加得出来的结果放在c[0]里面------ for (i=1;c[i][0];i++){strcpy(c[0],add_together(c[0],c[i]));}return c[0];}bool contrast(char *a,char *b,int c)//检查a,b两个字符串的大小{inspect_char_valid(a,b);for (;*a=='0';a++);for (;*b=='0';b++);if (strlen(a)>strlen(b)|| (strlen(a)==strlen(b)&& strcmp(a,b)>=c))return 1;elsereturn 0;}void inspect_char_valid(char *a,char *b)//检查两个字符串是否有其他符号{for (int i=0;*(a+i);i++){if (*(a+i)<'0'||*(a+i)>'9'){printf("输入的第一组数字里面包含符号\n退出！！！");exit(0);}}for (int i=0;*(b+i);i++){if (*(b+i)<'0'||*(b+i)>'9'){printf("输入的第二组数字里面包含符号\n退出！！！");exit(0);}}}void printf_char(char *a)//输出字符串{if (a[0]=='-'){for (a++;*a=='0';a++);a--;a[0]='-';puts(a);}else{for (;*a=='0';a++);if (a[0]=='\0')a--;puts(a);}}。