贸易型企业网站建设,网站开发后台指什么,vps wordpress cpu占用过高,一二三四视频社区C程序设计语言 #xff08;第二版#xff09; 练习 4-8
练习 4-8 假定最多只压回一个字符。请相应地修改getch与ungetch这两个函数。
注意#xff1a;代码在win32控制台运行#xff0c;在不同的IDE环境下#xff0c;有部分可能需要变更。
IDE工具#xff1a;Visual St…C程序设计语言 第二版 练习 4-8
练习 4-8 假定最多只压回一个字符。请相应地修改getch与ungetch这两个函数。
注意代码在win32控制台运行在不同的IDE环境下有部分可能需要变更。
IDE工具Visual Studio 2010 代码块
#include stdio.h
#include stdlib.h
#include ctype.h
#include math.h
#include string.h#define MAXOP 100
#define NUMBER 0
#define MAXVAL 100
#define BUFSIZE 100
#define VAR 1int sp 0;
double val[MAXVAL];//char buf[BUFSIZE];
int bufp 0;
char buf 0;double variable[26];void push(double f){if(sp MAXVAL){val[sp] f;}else{printf(Error! Stack Full, cant push %g\n, f);}
}double pop(void){if(sp 0){return val[--sp];}else{printf(Error! Stack Empty!\n);return 0.0;}
}void printTop(void){if(sp 0){printf(Top: %g\n, val[sp-1]);}else{printf(Error! Stack Empty!\n);}
}void topCopy(void){if(sp 0 || sp MAXVAL){val[sp] val[sp-1];}else if(sp 0){printf(Error! Stack Empty!\n);}else{printf(Error! Stack Full!\n);}
}void swapTop(void){double temp;if(sp 2){temp val[sp-1];val[sp-1] val[sp-2];val[sp-2] temp;}else{printf(Cant Swap Top Number!\n);}
}void emptyStack(void){for(int i sp - 1; i 0; i--){val[i] 0;}sp 0;
}int getch(void){int c;c (buf ! 0) ? buf : getchar();buf 0;return c;
}void ungetch(int c){if(buf ! 0){printf(Ungetch! Too many characters!\n);}else{buf c;}
}void ungets(char s[]){int len strlen(s);for(int i 0; i len; i){ungetch(s[i]);}
}int getop(char s[]){int i, c;while((s[0] c getch()) || c \t);s[1] \0;if(c s){int next1 getch();int next2 getch();if(next1 i next2 n){return c;}}if(c e){int next1 getch();int next2 getch();if(next1 x next2 p){return c;}}if(c p){int next1 getch();int next2 getch();if(next1 o next2 w){return c;}}if(c a c z){int next getch();if(next ){ungetch(next);return VAR;}}if(c -){int next getch();if(!isdigit(next) next ! .){ungetch(next);return c;}s[1] c next;i 1;}else{i 0;if(!isdigit(c) c ! .){return c;}}if(isdigit(c)){while(isdigit(s[i] c getch()));}if(c .){while(isdigit(s[i] c getch()));}s[i] \0;if(c ! EOF){ungetch(c);}return NUMBER;
}int main(){int type;double op2;char s[MAXOP];while((type getop(s)) ! EOF){switch(type){case NUMBER:push(atof(s));break;case :push(pop() pop());break;case *:push(pop() * pop());break;case -:op2 pop();push(pop() - op2);break;case /:op2 pop();if(op2 ! 0.0){push(pop() / op2);}else{printf(Error! Zero Divisor!\n);}break;case %:op2 pop();push((int)pop() % (int)op2);break;case s:op2 pop();push(sin(op2));break;case e:op2 pop();push(exp(op2));break;case p:op2 pop();push(pow(pop(), op2));break;case VAR:variable[s[0] - a] pop();push(variable[s[0] - a]);printf(%c %lf\n, s[0], variable[s[0] - a]);break;case \n:printf(\t%.8g\n, pop());break;default:printf(Error! Unknown Command %s\n, s);break;}}system(pause);return 0;
}
