201524653_Lab14_my_fscanf

.gitignore

@@ -0,0 +1,2 @@
+*.o
+/calc

calc.c

@@ -1,35 +1,38 @@
 #include <stdio.h>
 #include "operators.h"
+#include "my_fscanf.h"
 
-int main(){
-	FILE *fp = NULL;
+int main() {
+	FILE *fp = fopen("read.txt", "r");
 	int operand1, operand2;
 	char operator = ' ';
-	int result, line = 0;
+	int line = 0;
+	double(*calculator)(int, int);
 
-	fp = fopen("read.txt","r");
-	if(fp!=NULL){
-		fscanf(fp, "%d", &line);
-
-		for(int i=0; i<line; i++) {
-			fscanf(fp, "%d %c %d",&operand1, &operator, &operand2);
-			switch(operator) {
-				case '+':
-				result = add(operand1, operator);
+	fp = fopen("read.txt", "r");
+	if (fp != NULL) {
+		my_fscanf(fp, "%d", &line);
+
+		for (int i = 0; i<line && !feof(fp); i++) {
+			my_fscanf(fp, "%d %c %d", &operand1, &operator, &operand2);
+			switch (operator) {
+			case '+':
+				calculator = add;
+				break;
+			case '-':
+				calculator = minus;
 				break;
-				case '-':
-				result = minus(operand1, operator);
+			case '*':
+				calculator = mul;
 				break;
-				case '*':
-				result = mul(operand1, operator);
-				case '/':
-				result = div(operand1, operator);
+			case '/':
+				calculator = div;
 				break;
-			}		
-			printf("%d %c %d = %d\n",
-				 operand1, operator, operand2, result);
+			}
+
+			printf("%d %c %d = %lf\n",
+				operand1, operator, operand2, calculator(operand1, operand2));
 		}
 	}
 	return 0;
 }
-

my_fscanf.c

@@ -0,0 +1,43 @@
+// file: my_fscanf.c
+#include "my_fscanf.h"
+#include <stdarg.h>
+#include <ctype.h>
+void my_fscanf(FILE *fp, const char *format, ...) {
+	va_list list;
+	va_start(list, format);
+	while (*format) {
+		if (*format == '%') {
+			int c;
+			format++;
+			switch (*format) {
+			case 'd':
+			{
+				while (isspace(c = getc(fp))) {}
+
+				int* addr = va_arg(list, int*);
+				*addr = 0;
+				while (isdigit(c)) {
+					*addr = *addr * 10 + c - '0';
+					c = getc(fp);
+				}
+
+				while (isspace(c = getc(fp))) {}
+
+				ungetc(c, fp);
+				break;
+			}
+			case 'c':
+				{
+					while (isspace(c = getc(fp))) {}
+
+					char* addr = va_arg(list, char*);
+					*addr = c;
+					break;
+				}
+			}
+		}
+		else
+			format++;
+	}
+	va_end(list);
+}

my_fscanf.h

@@ -0,0 +1,6 @@
+// file: my_fscanf.h
+#ifndef MY_FSCANF_H
+#define MY_FSCANF_H
+#include <stdio.h>
+void my_fscanf(FILE *fp, const char *format, ...);
+#endif /* !MY_FSCANF_H */

operators.c

@@ -1,16 +1,16 @@
 #include "operators.h"
 
-int add(int op1, int op2) {
+double add(int op1, int op2) {
 	return op1+op2;
 }
-int minus(int op1, int op2) {
+double minus(int op1, int op2) {
 	return op1-op2;
 }
-int mul(int op1, int op2) {
+double mul(int op1, int op2) {
 	return op1*op2;
 }
 
-int div(int op1, int op2) {
-	return op1%op2;
+double div(int op1, int op2) {
+	return (double)op1/op2;
 }
 

operators.h

@@ -1,4 +1,4 @@
-int add(int op1, int op2);
-int mul(int op1, int op2);
-int div(int op1, int op2);
-int minus(int op1, int op2);
+double add(int op1, int op2);
+double mul(int op1, int op2);
+double div(int op1, int op2);
+double minus(int op1, int op2);