test.c

数学表达式计算和解析 用c语言编写的,内含有例.速度较快

/*
    File: test.c
    Auth: Brian Allen Vanderburg II
    Date: Thursday, May 1, 2003
    Desc: Test application for ExprEval library
*/

/* Includes */
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <setjmp.h>

#include "expreval.h"

/* Test function */
EXPR_FUNCTIONSOLVER(my_func)
    {
    EXPRTYPE tmp;
    int err;

    EXPR_REQUIREREFCOUNT(1);
    EXPR_REQUIRECOUNT(1);

    EXPR_EVALNODE(0, tmp);

    /* Set first ref item to the value of the parameter */
    *refitems[0] = tmp;
    *val = tmp;

    return EXPR_ERROR_NOERROR;
    }


int breaker(exprObj *o)
    {
    return kbhit();
    }

void main(void)
    {
    char buf[2048];
    char cbuf[2048];
    int pos, count;
    exprObj *e;
    exprFuncList *f;
    exprValList *v;
    exprValList *c;
    int err;
    EXPRTYPE val;
    time_t t1, t2;
    jmp_buf jumper;
    double diff;
    EXPRTYPE *e_pos, *e_res;

    /* Seed random number generator */
    srand((clock() + 1024) * time(NULL));

    /* Set error buffer */
    err = setjmp(jumper);
    if(err != 0)
        {
        /* Free stuff */
        exprFree(e);
        exprFuncListFree(f);
        exprValListFree(c);
        exprValListFree(v);

        if(err != -1)
            printf("Error: %d\n", err);

        return;
        }

    /* Get an expression */
    printf("Enter expression: ");
    gets(buf);  

    /* How many times to execute the expression */
    printf("Count: ");
    gets(cbuf);
    count = atoi(cbuf);

    /* Create funclist */
    err = exprFuncListCreate(&f);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Func List Creation Error\n");
        longjmp(jumper, 1);
        }

    /* Add a function */
    exprFuncListAdd(f, my_func, "myfunc", 1, 1, 1, 1);

	
    /* Init funclist */
    err = exprFuncListInit(f);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Error initializing internal functions\n");
        longjmp(jumper, err);
        }

    /* Create varlist */
    err = exprValListCreate(&v);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Var List Creation Error\n");
        longjmp(jumper, err);
        }

    /* Create constlist */
    err = exprValListCreate(&c);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Const List Creation Error\n");
        longjmp(jumper, err);
        }

    /* Init constlist */
    err = exprValListInit(c);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Error initializing internal constants\n");
        longjmp(jumper, err);
        }

    err = exprValListAdd(v, "pos", 0.0);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Error adding variable \'pos\'\n");
        longjmp(jumper, err);
        }

    err = exprValListAdd(v, "res", 0.0);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Error adding variable \'res\'\n");
        longjmp(jumper, err);
        }

    exprValListGetAddress(v, "pos", &e_pos);
    exprValListGetAddress(v, "res", &e_res);

    if(e_pos == NULL || e_res == NULL)
        {
        printf("Unable to get address of \'pos\' or \'res\'\n");
        longjmp(jumper, EXPR_ERROR_UNKNOWN);
        }

	

    /* Create expr */
    err = exprCreate(&e, f, v, c, NULL, breaker, 0);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Expr Creation Error\n");
        longjmp(jumper, err);
        }

    /* Parse expr */
    err = exprParse(e, buf);
    if(err != EXPR_ERROR_NOERROR)
        {
        printf("Parse Error\n");
        longjmp(jumper, err);
        }

    /* Eval expression */
    exprSetSoftErrors(e, 0);

    t1 = time(NULL);

    for(pos = 0; pos < count; pos++)
        {
        *e_pos = (EXPRTYPE)pos;

        err = exprEval(e, &val);
#if(1)
        if(err != EXPR_ERROR_NOERROR)
	        printf("Eval Error: %d\n", err);
#endif
        }

		
    t2 = time(NULL);
    diff = difftime(t2, t1);


    printf("Final Value: %f\n", val);
    printf("Time: %f\n", diff);
    printf("Average Time Each: %f\n", diff / (double)count);
    if(diff != 0.0)
        printf("Average Evaluations/Second: %f\n", (double)count / diff);

#ifdef EXPR_FAST_VAR_ACCESS
    printf("res=: %f\n", *e_res);
#else
    if(exprValListGet(v, "res", &val) == EXPR_ERROR_NOERROR)
        printf("res=: %f\n", val);
#endif

    /* We are done */
    longjmp(jumper, -1);
	}