Merge pull request #546 from medymik/master

atoi

conversions/c_atoi_str_to_integer.c

@@ -0,0 +1,80 @@
+/**
+ * \file
+ * \brief Recoding the original atoi function in stdlib.h 
+ * \author [Mohammed YMIK](https://github.com/medymik)W
+ * The function convert a string passed to an integer 
+ */
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ * the function take a string and return an integer
+ * \param[out] str pointer to a char address
+ */
+int c_atoi(const char *str)
+{
+    int     i;
+    int     sign;
+    long    value;
+    long    prev;
+
+    i = 0;
+    sign = 1;
+    value = 0;
+
+    /* skipping the spaces */
+    while (((str[i] <= 13 && str[i] >= 9) || str[i] == 32) && str[i] != '\0')
+        i++;
+
+    /* store the sign if it is negative sign */
+    if (str[i] == '-' || str[i] == '+')
+        (str[i++] == '-') ? sign = -1 : 1;
+
+    /* converting char by char to a numeric value */
+    while (str[i] >= 48 && str[i] <= 57 && str[i] != '\0')
+    {
+        prev = value;
+        value = value * 10 + sign * (str[i] - '0');
+
+        /* managing the overflow */
+        if (sign == 1 && prev > value)
+            return (-1);
+        else if (sign == -1 && prev < value)
+            return (0);
+        i++;
+    }
+    return (value);	
+}
+
+/**
+ * test the function implementation
+ */
+int test_c_atoi()
+{
+    printf("<<<< TEST FUNCTION >>>>\n");
+    assert(c_atoi("123") == atoi("123"));
+    assert(c_atoi("-123") == atoi("-123"));
+    assert(c_atoi("") == atoi(""));
+    assert(c_atoi("-h23") == atoi("-h23"));
+    assert(c_atoi("         23") == atoi("         23"));
+    assert(c_atoi("999999999999") == atoi("999999999999"));
+    printf("<<<< TEST DONE >>>>\n");
+}
+
+
+/**
+ * the main function take one argument of type char*
+ * example : ./program 123
+ */
+int	main(int argc, char **argv)
+{
+    if (argc == 2)
+    {
+        printf("Your number + 5 is %d\n", c_atoi(argv[1]) + 5);
+        return (0);
+    }
+    printf("wrong number of parmeters\n");
+    return (1);
+}