#include
#include
void main(){
char c1,c2;
int n=0,k=0,t=0;
double sum;
double d[100];
printf("请输入公式:");
c1=getchar();
while(c1!='\n'){
d[n]=c1;
c2=getchar();
if(c1>47&&c1<58){
d[n]=c1-48;
while(c2>47&&c2<58){
d[n]=d[n]*10+(c2-48);
c2=getchar();
}
}
if(c2=='.'){
double k=0.1;
while((c2=getchar())>47&&c2<58){
d[n]=d[n]+(c2-48)*k;
k*=0.1;
}
}
c1=c2;
n++;
}
d[n]='\n';
for(int i1=1;i1 if(d[i1]=='/'){ d[i1]='*'; if(d[i1+1]==0){ printf("零不能为除数."); exit(0); } d[i1+1]=1/d[i1+1]; } for(int i=1;d[i]!='\n';i++) if(d[i]=='*'){ d[i-1]=d[i-1]*d[i+1]; k=i-1; while(i+2 i+=2; d[k]=d[k]*d[i+1]; } for(int j=0;j d[k+1+j]=d[i+2+j]; } sum=d[0]; for(int j1=2;d[j1]!='\n';j1++){ if(d[j1-1]=='+') sum=sum+d[j1]; if(d[j1-1]=='-') sum=sum-d[j1]; } printf("=%.3f\n",sum); }