个人网站备案拍照,彩票网站建设柏,新手做自媒体从哪开始,建设电器网站目的及功能定位一、程序功能描述
本程序由C/C编写#xff0c;实现了赋值语句语法制导生成四元式#xff0c;并完成了语法分析和语义分析过程。
以专题 1 词法分析程序的输出为语法分析的输入#xff0c;完成以下描述赋值语句 SLR(1)文法的语义分析及中间代码四元式的过程#xff0c;实现…
一、程序功能描述
本程序由C/C编写实现了赋值语句语法制导生成四元式并完成了语法分析和语义分析过程。
以专题 1 词法分析程序的输出为语法分析的输入完成以下描述赋值语句 SLR(1)文法的语义分析及中间代码四元式的过程实现编译器前端。
G[S]: S→VE
E→ET∣E-T∣T
T→T*F∣T/F∣F
F→(E)∣i
V→i
二、主要数据结构描述 关于本程序的数据结构首先用map存储了非终结符及终结符的编码映射而后用string存储文件读入和写入的信息等最重要的是利用vector二维数组实现了SLR分析表用于存储分析动作此外定义了四元组和栈的相应结构体。由于本人习惯字符串处理总体上采用了C风格和C方式并存的写法。
、程序结构描述 除main函数外本程序共定义了4个函数 getIndex用于返回输入字符在deCode 映射中的对应索引若非法字符则返回-1。
dispQuad用于显示解析过程中生成的四元组并展示输入表达式的中间代码表示SLR_display则显示分析栈的当前状态、剩余的输入字符串以及解析过程中的当前动作。这两个函数都用于实现编译前端的可视化。 在SLR_analysis真正实现了SLR(1)文法的分析过程使用栈 (anstk) 跟踪解析过程中的状态、符号和输入字符串位置并根据 SLR 解析表执行移入、规约和接受等动作最后在解析过程中生成四元组表示中间代码。
四、程序测试 测试案例展示如下 测试用例1a((b)c*d)/fe*g #includeiostream
#includecstring
#includestring
#includevector
#includemap
using namespace std;
const int N1024;
string testFileName test4.txt;
string info[3] {---------------------------, SLR(1)分析, ---------------------------};
mapchar, int deCode
{{i, 0},{, 1},{, 2},{-, 3},{*, 4},{/, 5},{(, 6},{), 7},{#, 8},{S, 9},{E, 10},{T, 11},{F, 12},{V, 13},
};
vectorvectorinttable {{ 3, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2},{ 0, 0, 0, 0, 0, 0, 0, 0,-11,0,0, 0, 0, 0},{ 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},{-10,-10,-10,-10,-10,-10,-10,-10,-10, 0, 0, 0, 0, 0},{ 9, 0, 0, 0, 0, 0, 8, 0, 0, 0, 5, 6, 7, 0},{-1,-1,10,11,-1,-1,-1,-1,-1, 0, 0, 0, 0, 0},{-4,-4,-4,-4,12,13,-4,-4,-4, 0, 0, 0, 0, 0},{-7,-7,-7,-7,-7,-7,-7,-7,-7, 0, 0, 0, 0, 0},{ 9, 0, 0, 0, 0, 0, 8, 0, 0, 0,14, 6, 7, 0},{-9,-9,-9,-9,-9,-9,-9,-9,-9, 0, 0, 0, 0, 0},{ 9, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0,15, 7, 0},{ 9, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0,16, 7, 0},{ 9, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0,17, 0},{ 9, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0,18, 0},{ 0, 0,10,11, 0, 0, 0,19, 0, 0, 0, 0, 0, 0},{-2,-2,-2,-2,12,13,-2,-2,-2, 0, 0, 0, 0, 0},{-3,-3,-3,-3,12,13,-3,-3,-3, 0, 0, 0, 0, 0},{-5,-5,-5,-5,-5,-5,-5,-5,-5, 0, 0, 0, 0, 0},{-6,-6,-6,-6,-6,-6,-6,-6,-6, 0, 0, 0, 0, 0},{-8,-8,-8,-8,-8,-8,-8,-8,-8, 0, 0, 0, 0, 0}};struct quadruple {char op[N];char arg1[N];char arg2[N];char res[N];
};
struct quadruple quad[N];
int topOfQuad 0; struct Stack {char s[N];int i[N];int space[N];int top;
}; int getIndex(char ch);
int SLR_analysis(char *str, struct Stack *anstk);
void SLR_display(char *str, struct Stack *anstk, int cur);
void dispQuad();int main() {for (int i 0; i 3; i)cout info[i] endl;FILE *fp fopen(testFileName.c_str(), r);char buf[N] ;char input[N] ;fgets(buf, N, fp);int j 0;for(int k 0; k strlen(buf); k) { if(buf[k] 1 buf[k1] ,) {k 3;while(1) {if(buf[k] ) buf[k1] )break;input[j] buf[k];}continue;}if(buf[k] , buf[k1] ) {k 2;while(1) {if(buf[k] ) buf[k1] )break;input[j] buf[k];}}}printf(输入表达式为: %s\n, input); input[j] #; fclose(fp);struct Stack *anstk;anstk (struct Stack *)malloc(sizeof(struct Stack));anstk-s[0] #;anstk-i[0] 0;anstk-space[0] -1;anstk-top 0; if(!SLR_analysis(input, anstk)) {cout 语法错误 endl;}else {cout 分析成功 endl;dispQuad(); }return 0;
}int getIndex(char ch) {if (deCode.find(ch) ! deCode.end())return deCode[ch];elsereturn -1;
}void SLR_display(char *str, struct Stack *anstk, int cur) { for(int i 0; i anstk-top; i) {cout anstk-s[i];}for(int i 0; i 3-(anstk-top1)/8; i) {cout \t;}for(int i cur; i strlen(str); i) {cout str[i];}printf(\n);
}void dispQuad() { printf(四元式:\n);for(int i 1; i topOfQuad; i) {printf((%s, %s, %s, %s)\n, quad[i].op, quad[i].arg1, quad[i].arg2, quad[i].res);}
}int SLR_analysis(char *str, struct Stack *anstk) { topOfQuad 0;int i 0;int next;printf(分析栈:\t\t\t字符串:\t\t\t动作:\n);while(i strlen(str)) {if(anstk-top 0) return 0; int y; if (str[i] a str[i] z) y getIndex(i); else y getIndex(str[i]);if(y -1 || table[anstk-i[anstk-top]][y] 0) { return 0;}if(table[anstk-i[anstk-top]][y] 0) { next table[anstk-i[anstk-top]][y];anstk-top;anstk-s[anstk-top] str[i];anstk-i[anstk-top] next;anstk-space[anstk-top] i;i;SLR_display(str, anstk, i);}else if(table[anstk-i[anstk-top]][y] 0) { int tmp -table[anstk-i[anstk-top]][y]; if(tmp 4 || tmp 7 || tmp 9 || tmp 10) {anstk-top--; }else if(tmp 2 || tmp 3 || tmp 5 || tmp 6){topOfQuad;if(tmp 2) strcpy(quad[topOfQuad].op, );else if(tmp 3) strcpy(quad[topOfQuad].op, -);else if(tmp 5) strcpy(quad[topOfQuad].op, *);else strcpy(quad[topOfQuad].op, /);if(anstk-space[anstk-top - 2] 0) sprintf(quad[topOfQuad].arg1, t%d, -anstk-space[anstk-top - 2]);else {char arg1[2] {str[anstk-space[anstk-top - 2]], \0};strcpy(quad[topOfQuad].arg1, arg1);}if(anstk-space[anstk-top] 0) sprintf(quad[topOfQuad].arg2, t%d, -anstk-space[anstk-top]);else {char arg2[2] {str[anstk-space[anstk-top]], \0};strcpy(quad[topOfQuad].arg2, arg2);}cout \t\t\t\t\t\t;printf(t%d %s %s %s\n, topOfQuad, quad[topOfQuad].arg1, quad[topOfQuad].op, quad[topOfQuad].arg2); sprintf(quad[topOfQuad].res, t%d, topOfQuad);anstk-top - 3; anstk-space[anstk-top 1] -topOfQuad; }else if(tmp 8) {anstk-top - 3; anstk-space[anstk-top 1] anstk-space[anstk-top 2]; }else if(tmp 1){topOfQuad;strcpy(quad[topOfQuad].op, );if(anstk-space[anstk-top] 0) sprintf(quad[topOfQuad].arg1, t%d, abs(anstk-space[anstk-top]));else {char arg1[2] {str[anstk-space[anstk-top]], \0};strcpy(quad[topOfQuad].arg1, arg1);}sprintf(quad[topOfQuad].arg2, );char res[2] {str[anstk-space[anstk-top - 2]], \0};strcpy(quad[topOfQuad].res, res);cout \t\t\t\t\t\t;printf(%s %s\n, quad[topOfQuad].res, quad[topOfQuad].arg1);anstk-top - 3; }else anstk-top - 3;if(tmp 1) { y getIndex(S);next table[anstk-i[anstk-top]][y]; anstk-top;anstk-s[anstk-top] S;anstk-i[anstk-top] next; }else if(tmp 2 || tmp 3 || tmp 4) {y getIndex(E);next table[anstk-i[anstk-top]][y]; anstk-top;anstk-s[anstk-top] E;anstk-i[anstk-top] next;}else if(tmp 5 || tmp 6 || tmp 7) {y getIndex(T);next table[anstk-i[anstk-top]][y];anstk-top;anstk-s[anstk-top] T;anstk-i[anstk-top] next;}else if(tmp 8 || tmp 9) {y getIndex(F);next table[anstk-i[anstk-top]][y];anstk-top;anstk-s[anstk-top] F;anstk-i[anstk-top] next;}else if(tmp 10) {y getIndex(V);next table[anstk-i[anstk-top]][y];anstk-top;anstk-s[anstk-top] V;anstk-i[anstk-top] next;}else if(tmp 11) {return 1; }SLR_display(str, anstk, i);}}return 0;
}
