显示代码纯文本
#include<cstdio>
#include<cctype>
#include<cstring>
char str[1000];
int main(){
freopen("computer.in","r",stdin);
freopen("computer.out","w",stdout);
scanf("%s",str+1);
int n=strlen(str+1);
char var;int mid;
for(int i=1;i<=n;++i){
if(isalpha(str[i]))var=str[i];
if(str[i]=='=')mid=i;
}
int a=0,b=0;//ax+b==0
int x=0;bool minus=false;
for(int i=1;i<mid;++i){
if(str[i]==var){
if(x==0)x=1;
a+=(minus?x:-x);x=0;minus=false;
}else if(str[i]=='-'){
b+=(minus?x:-x);x=0;minus=true;
}else if(str[i]=='+'){
b+=(minus?x:-x);x=0;minus=false;
}else{
x=x*10+str[i]-'0';
}
}
if(x!=0){
b+=(minus?x:-x);x=0;minus=false;
}
for(int i=mid+1;i<=n;++i){
if(str[i]==var){
if(x==0)x=1;
a-=(minus?x:-x);x=0;minus=false;
}else if(str[i]=='-'){
b-=(minus?x:-x);x=0;minus=true;
}else if(str[i]=='+'){
b-=(minus?x:-x);x=0;minus=false;
}else{
x=x*10+str[i]-'0';
}
}
if(x!=0){
b-=(minus?x:-x);x=0;minus=false;
}
printf("%c=%.3f\n",var,-b*1.0/a);
fclose(stdin);fclose(stdout);
return 0;
}