没括号就是这样,getchar()调一调格式,注意出现除法时,不要用整型

#include <stdio.h>

int main() {
    float val[100];
    while (scanf("%f", &val[0]) != EOF) {
        char top=0, c;
        while(getchar()!='\n' && scanf("%c", &c)){
            scanf("%f", &val[++top]);
            if(c=='-') val[top] *= -1;
            else if(c=='/') {val[top-1] /= val[top]; --top;}
            else if(c=='*') {val[top-1] *= val[top]; --top;}
        }if(val[0]==0&&top==0) break;
        for(int i=1; i<=top; ++i) val[0] += val[i];
        printf("%.2f\n", val[0]);
    }
    return 0;
}