First commitHEADmain

1 files changed, 192 insertions, 0 deletions

diff --git a/my_atoi.c b/my_atoi.c
new file mode 100644
index 0000000..c5b0642
--- /dev/null
+++ b/my_atoi.c
@@ -0,0 +1,192 @@
+// TODO: add decimal point hex and octal support
+// TODO: add limit to maximum imput allowed
+#include <stdio.h> //printf(), fprintf()
+#include <assert.h> //assert()
+#include <stdlib.h> //exit()
+#include <stdbool.h> //_Bool, false, true
+#include "my_atoi.h"
+
+#define ASCIIFIRST 48
+#define ASCIILAST  57 
+#define NULL '\0'
+
+double my_atoi(char* str)
+{
+	int i = 0, start = 0, base = 10, floatIndex;
+	double num2Convert = 0;
+	_Bool boolHex = false, boolOctal = false, boolNegative = false, boolFloat = false, priorZero = false;
+	
+//017 -017 no decimals for hex or octal NULL, -NULL, .NULL, 0xNULL, 0XNULL, -.NULL, -0xNULL, -0XNULL, 0x., -0x., 0X., -0X., -0[8,9,a-f,A-F],  xX can only be in the second or third index 8-9, a-f, A-F, -, ., xX octal: - 0-7 decimal: - . 0-9 hex: 0-9 a-f A-F - xX
+
+if (str[0] == '-') {
+	boolNegative = 1;
+	++start;
+	++i;
+}
+
+do {
+	switch (str[i]) {
+		case '0':
+			if (!priorZero) {
+				priorZero = true;
+				if (i == 0 || (i == 1 && boolNegative)) {
+					if (str[i + 1] == NULL) {
+						return 0;
+					} else if (str[i + 1] == '.') {
+						boolFloat = 1;
+						floatIndex = i = 1;
+						++i;
+					} else {
+						boolOctal = 1;
+						++start;
+					}
+				}
+			}
+			break;
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+			break;
+		case '8':
+		case '9':
+			if (boolOctal) {
+				fprintf(stderr, "ERROR: %c is an invalid input for octal numbers\n", str[i]);
+				exit(-1);
+			}
+			break;
+		case 'a':
+		case 'A':
+		case 'b':
+		case 'B':
+		case 'c':
+		case 'C':
+		case 'd':
+		case 'D':
+		case 'e':
+		case 'E':
+		case 'f':
+		case 'F':
+			if (!boolHex) {
+				fprintf(stderr, "ERROR: %c is an invalid input for octal and/or decimal numbers\n", str[i]);
+				exit(-1);
+			}
+			break;
+		case '.':
+			if (boolFloat) {
+				fprintf(stderr, "ERROR: String contains more than one '.'\n");
+				exit(-1);
+			} else if (boolHex || boolOctal) {
+				fprintf(stderr, "ERROR: Currently not accepting hexidecimal or octal floating point numbers.\n");
+				exit(-1);
+			} else {
+				boolFloat = 1;
+				floatIndex = i;
+			}
+			break;
+		case NULL:
+			if (i == 0 || str[i - 1] == '-' || str[i - 1] == 'x' || str[i - 1] == 'X'){
+				fprintf(stderr, "ERROR: Entered an empty number.\n");
+				exit(-1);
+			}
+			break;
+		case 'x':
+		case 'X':
+			if (i != 1 && i != 2 && str[i - 1] != 0) {
+				fprintf(stderr, "ERROR: 'x or X' characters can only be included once and must be preceeded by a 0.\n");
+				exit(-1);
+			} 
+			boolOctal = 0;
+			boolHex = 1;
+			++start;
+			break;
+		default:
+			fprintf(stderr, "ERROR: Invalid character included.\n");
+			exit(-1);
+	}
+	++i;
+} while (str[i] != NULL); //when this is done I will be the number of characters including null termination
+
+
+	if (boolHex) {
+		for (int j = i - 1, multi = 1, base = 16; j > start - 1; multi *= base, --j) {
+			switch (str[j]) {
+				case '0':
+				case '1':
+				case '2':
+				case '3':
+				case '4':
+				case '5':
+				case '6':
+				case '7':
+				case '8':
+				case '9':
+					num2Convert += (multi * (str[j] - ASCIIFIRST));
+					break;
+				case 'a':
+				case 'A':
+					num2Convert += multi * 10;
+					break;
+				case 'b':
+				case 'B':
+					num2Convert += multi * 11;
+					break;
+				case 'c':
+				case 'C':
+					num2Convert += multi * 12;
+					break;
+				case 'd':
+				case 'D':
+					num2Convert += multi * 13;
+					break;
+				case 'e':
+				case 'E':
+					num2Convert += multi * 14;
+					break;
+				case 'f':
+				case 'F':
+					num2Convert += multi * 15;
+					break;
+				default:
+					fprintf(stderr, "ERROR: out of bounds character for hexadecimal. Only use 0-9,Aa-Ff\n");
+			}
+		}
+	} else if (boolOctal) {
+		for (int j = i - 1, multi = 1, base = 8; j > start - 1; multi *= base, --j) {
+			if (str[j] > ASCIILAST - 2) {
+				fprintf(stderr, "ERROR: out of bounds range for octal number. Only use 0-7.\n");
+			} else {
+				num2Convert += multi * (str[j] - ASCIIFIRST);
+			}
+		}
+	} else if (boolFloat) {
+		fprintf(stderr, "NEED TO FIGURE OUT HOW TO CONVERT FLOATS STILL\n");
+		//count distance from end -1 to floatIndex and take that number and divide it by the appropriate multiple of 10
+		//then do the portion to the left of the decimal the exact same as usual
+		{
+		double multi = .1;
+		for (int j = floatIndex + 1, base = 10;  j < i; multi /= base, ++j) {
+				num2Convert += multi * (str[j] - ASCIIFIRST); 
+		}
+		}
+		for (int j = floatIndex - 1, multi = 1, base = 10; j >= start; multi *= base, --j) {
+				num2Convert += multi * (str[j] - ASCIIFIRST); 
+		}
+	} else {
+		for (int j = i - 1, multi = 1, base = 10; j >= start; multi *= base, --j) {
+				num2Convert += multi * (str[j] - ASCIIFIRST); 
+		}
+	}
+
+	if (boolNegative) {
+		num2Convert *= -1;
+	}
+
+	printf("boolHex: %d, boolOctal: %d, boolFloat: %d, boolNegative: %d, \n", boolHex, boolOctal, boolFloat, boolNegative);
+
+	return num2Convert;
+
+}