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main.c
149 lines (116 loc) · 3 KB
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main.c
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// Simple Scheme Compiler
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef double (*operator)(int, int);
int parse_number(char **Ptr);
operator parse_operator(char **Ptr);
double add (int left, int right);
double sub (int left, int right);
double mul (int left, int right);
double divio (int left, int right);
void error ();
/* Überprüfen des Operators */
operator parse_operator(char **Ptr) {
if ((**Ptr) == '+') {
return add;
}
if ((**Ptr) == '-') {
return sub;
}
if ((**Ptr) == '*') {
return mul;
}
if ((**Ptr) == '/') {
return divio;
}
}
/* addition funktion */
double add (int left, int right) {
return left+right;
}
/* sub funk */
double sub (int left, int right) {
return left-right;
}
/* mul funk */
double mul (int left, int right) {
return left*right;
}
/* div funk */
double divio (int left, int right) {
return left/right;
}
/* Numern zusammenzählen */
int parse_numb(char **Ptr, int number) {
if ((**Ptr) >= '0' && (**Ptr) <= '9') {
number = number*10 + ((**Ptr) - '0');
return number;
}
error();
}
/* error func */
void error () {
printf("fehler");
exit(0);
}
int main()
{
char *zPtr = NULL;
operator op = NULL;
int number = 0;
int erg = 0;
int buffer_size = 0;
int n=0;
FILE *fp = fopen("./data", "r");
if (fp == NULL) {
error();
}
fseek(fp, 0, SEEK_END);
buffer_size = ftell(fp);
fseek(fp, 0, SEEK_SET);
printf("size of buffer: %i\n", buffer_size);
char *content_buffer = malloc(buffer_size);
if (content_buffer == NULL) {
error();
}
fgets(content_buffer, buffer_size+1, fp);
printf("buffer content: %s\n",content_buffer);
printf("\nPos. \t read number \t memory ");
for(;n < buffer_size ;n++) {
/* Leerzeichen */
if(*content_buffer == ' ') {
printf("\n-----------------------------------");
zPtr=content_buffer;
content_buffer++;
continue;
}
/* Operatoren */
if( op == NULL) {
op = parse_operator(&content_buffer);
content_buffer++;
continue;
}
/* Prozess */
if( content_buffer == (zPtr+1)) {
/* Überprüfen ob eine Zahl im Speicher vorhanden ist */
if(erg == 0) {
erg = number;
number = 0; /* Zwischenspeicher auf Null setzten */
}
else {
erg = op(erg, number); /* Berrechnung der neuen Zahl */
number = 0; /* Zwischenspeicher auf Null setzten */
}
}
/* number parse */
number = parse_numb(&content_buffer,number);
printf("\n%i \t %d \t\t %d ", n, number, erg);
content_buffer++;
}
printf("\n-----------------------------------");
erg = op(erg, number);
printf("\nfinal result: %2d \n", erg);
free(fp);
return 0;
}