Diff: main.cpp

Revision:

1:247161a5c5d6

Parent:

0:879aa9d0247b

Child:

2:0baf535ed8f8

--- a/main.cpp	Tue Feb 12 17:39:05 2013 +0000
+++ b/main.cpp	Mon Sep 22 03:12:09 2014 +0000
@@ -1,10 +1,105 @@
 #include "mbed.h"
- 
+
+#define FALSE 0
+#define TRUE 1
+
 Serial pc(USBTX, USBRX); // tx, rx
+
+// function to convert a char buffer to decimal inetger
+int char_to_int (const char *char_p, const int size)
+{
+    int tmp = 0;
+    int pot_ten=1;
+    for ( int i= (size -1); i >= 0 ; i-- ) {
+        tmp = int( tmp + ( ( int(char_p[i]) - 48 ) * pot_ten ));
+        pot_ten*=10;
+        //pc.printf("\n");
+        //print_num(tmp);
+        //pc.printf("\n");
+        //print_num(pot_ten);
+    }
+    return tmp;
+}
+
+
+// check if the input is valid
+bool si_check_valid(const char & input)
+{
+    if ( ( ( int(input) > 57) || ( int(input) < 48) ) && (input != '+') && (input != '-') && (input != '*') && (input != '/') && (input != '=') ) {
+        return FALSE;
+    } else {
+        return TRUE;
+    }
+}
+
+//check if the input is a number
+bool si_check_number(const char & input)
+{
+    if ( (int(input) >= 48) && ( int(input) <= 57) ) {
+        return TRUE;
+    } else {
+        return FALSE;
+    }
+}
+
  
-int main() {
-    pc.printf("Hello World!\n");
+
+int main()
+{
+    char c;
+    char op = '=';
+    char operand [100];
+    char buf[10];
+    int result =0;
+    int index = 0;
+    bool first = TRUE;
+
+    pc.printf("LPC Integer Calculator!\n");
+    
     while(1) {
-        pc.putc(pc.getc() + 1);
+ 
+        c=pc.getc();  //get serial input
+
+        if (!si_check_valid(c)) { // Invalid Input
+            pc.putc(c);
+            printf ("Invalid Input!\n");
+        } else if (si_check_number(c)) { // Operand has been entered
+            pc.putc(c);
+            operand[index] = c;
+            index++;
+        } else { //Operator has been entered
+        
+            pc.putc('\n');
+            pc.putc(c);
+            pc.putc('\n');
+
+            if (first) {  //First Operator
+                result = char_to_int(operand,index);
+                first = FALSE;
+            } else { //Do Calculation
+
+                if(op == '+') {
+                    result = int (result + char_to_int(operand,index));
+                } else if (op == '-') {
+                    result = int (result - char_to_int(operand,index));
+                } else if (op  == '/') {
+                    result = int (result / char_to_int(operand,index));
+                } else if (op == '*') {
+                    result = int (result * char_to_int(operand,index));
+                }
+
+                if (c == '=') { // Operator = has been entered--> Print result and reset calculator
+                    for (int j =9; j>=0; j--){buf[j]='\0';}
+                    sprintf(buf, "%d", result);
+                    pc.printf("%s", buf);
+                    pc.printf("\n\n");
+                    pc.printf("Please enter a new operation\n");
+                    first = TRUE;
+                }
+            }
+            op = c;  // assign the Operator
+            index=0; // reset the operand
+        }
     }
-}
\ No newline at end of file
+}
+