From 2f426f73597fd6e61f207a5e4f50519ab38af821 Mon Sep 17 00:00:00 2001
From: Calson Noah <chiacalson@gmail.com>
Date: Thu, 6 Jul 2017 13:08:42 +0100
Subject: [PATCH] added functions to manipulate console

---
 terminal.h | 165 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 165 insertions(+)
 create mode 100755 terminal.h

diff --git a/terminal.h b/terminal.h
new file mode 100755
index 0000000..e84d17c
--- /dev/null
+++ b/terminal.h
@@ -0,0 +1,165 @@
+
+float my_pow(float base, int exp)//mickmicking the pow function
+{
+    float temp;
+    if( exp == 0)
+       return 1;
+    temp = my_pow(base, exp/2);       
+    if (exp%2 == 0)
+        return temp*temp;
+    else
+    {
+        if(exp > 0)
+            return base*temp*temp;
+        else
+            return (temp*temp)/base;
+    }
+}
+
+
+//micking atoi function (returns integer from string) 
+static int my_atoi(const char* snum)
+{
+    int idx, str_idx = 0, accum = 0, num_is_neg = 0;
+    const unsigned int NUMLEN = (int)strlen(snum);
+
+    /* Check if negative number and flag it. */
+    if(snum[0] == 0x2d)
+        num_is_neg = 1;
+    for(idx = NUMLEN - 1; idx >= 0; idx--)
+    {
+        /* Only process numbers from 0 through 9. */
+        if(snum[str_idx] >= 0x30 && snum[str_idx] <= 0x39)
+            accum += (snum[str_idx] - 0x30) * my_pow(10, idx);
+        str_idx++;
+    }
+
+    /* Check flag to see if originally passed -ve number and convert result if so. */
+    if(!num_is_neg)
+        return accum;
+    else
+        return accum * -1;
+}
+
+//my library for single character input without echoing, **the conio.h is needed for windows systems.
+char get_char_necho()
+{
+	#if defined(__linux__)
+	/*prevent echoing of characters from the buffer*/
+    getche();
+    #elif defined(_WIN32)
+    #include<conio.h>
+    getch();
+    #endif
+}
+
+     /*prevent echoing of characters from the buffer*/
+extern int getche(void)//works with linux
+        {
+            struct termios oldattr, newattr;
+            int ch;
+            tcgetattr( STDIN_FILENO, &oldattr );
+            newattr = oldattr;
+            newattr.c_lflag &= ~( ICANON | ECHO);//shell out to kill echo
+            tcsetattr( STDIN_FILENO, TCSANOW, &newattr );
+            system("stty -echo");//shell out to kill echo
+            ch = getchar();
+            system("stty echo");
+            tcsetattr( STDIN_FILENO, TCSANOW, &oldattr );
+            return ch;
+        }
+
+/*Clears a the number of characters passed to it as parameter n*/
+extern void letter_clear(int n)
+    {
+        int i;
+        for(i=1;i<=n;i++)
+            printf("\b \b");//implementing a destructive backspace
+    }
+
+
+
+unsigned int is_integral(char number[], int argc_cmd)
+{
+    //printf("%s\n", number);
+    int i = 0;
+    if(number==NULL)
+    {
+        fprintf(stderr, "%s\n", "Fatal Error: Null argument");
+        exit(EXIT_FAILURE);
+    }
+  /*  if(my_atoi(number)==0)
+    {
+        fprintf(stderr, "%s\n", "Fatal Error: Lesson number cannot be zero");
+        exit(EXIT_FAILURE);
+    }*/
+    //checking for negative numbers
+    if (number[0] == '-')
+    {
+        fprintf(stderr, "%s\n", "Fatal error: Negative argument");
+        exit(EXIT_FAILURE);
+    }
+    if(argc_cmd==4)
+    {
+        if(strlen(number)<2||my_atoi(number)<10||my_atoi(number)>900)
+        {
+            fprintf(stderr, "%s\n", "Fatal Error: Either argument is not in range <45-900> OR argument is invalid");
+            exit(EXIT_FAILURE);
+        }
+    }
+    else
+    if(strlen(number)>2||my_atoi(number)>50||my_atoi(number)<1)
+    {
+        fprintf(stderr, "%s\n", "Fatal Error: Argument not in range <1-50> OR invalid");
+        exit(EXIT_FAILURE);
+    }
+    return my_atoi(number);//returns the unsigned integral string entered as argument at terminal
+}
+
+int range_verifier(int n)
+{
+    if(n<0||n>15)
+    {
+        fprintf(stderr, "%s\n", "Lesson number does not exist");
+        exit(EXIT_FAILURE);
+    }
+    return n;
+}
+
+
+//windows virtual command line; produces command line environment while in the program.
+//char v_cmd[81][81];//2d virtual array to hold the arguments as they are entered.
+//added an argument, to be removed if does not work and line 152 modified
+extern int win_cmd_arg(char **v_cmd, char *temp)
+{
+    printf("%s","%%noslac$>>");
+    char win_str[300];
+	int i=0,argc=0,j=0,u=0;	
+	
+	fgets(win_str,250,stdin);//reading arguments, uses \n to flush
+	if(strlen(win_str)>177||u>=15)//ensures the arguments are not more than 15 and size does not exceed 177
+	{
+		fprintf(stderr,"%s\n", "Invalid number of arguments");
+		exit(EXIT_FAILURE);
+	}
+	do
+	{
+		temp[j]=win_str[i];
+		if(temp[j]=='\n'||temp[j]==' ')
+		{
+			temp[j]='\0';
+			j=-1;	
+			v_cmd[u]=temp;
+		//	printf("u=%d, j=%d, i=%d v_cmd=%s\n",u,j,i,v_cmd[u]);	
+			//getchar();
+			if(temp[j]=='\n')
+				break;	
+			u++;
+		}
+		//printf("temp j=%d\n",j);
+		j++;		
+		i++;
+	}while(win_str[i]!=EOF);	
+	return u-1;//first element has index 0
+}
+