This page is written by a student who understand what problems a student has,so if you are student it will be very good for you

Any questions,comments,tips,..mail me

CONTENTS :

Some basic knowledge

FAQ

Source code

SOME BASIC KNOWLEDGE:

KEYWORD FUNCTION EXAMPLE INPUT EXAMPLE OUTPUT
printf prints the string written within the quotation marks printf("Hello"); Hello ,Use cout in C++
#include<stdio.h> calls the standard input/output function #include <stdio.h> Use #include <iostream.h> in C++
int main() creates main function to run the program int main() Use return var; to report to environment(DOS..)
scanf inputs a variable or string scanf("%d", &variableName); inputs a list of variables
%d %lf %d = an integer; %lf = a decimal number printf("%d", variableName); prints the variable amount

An example using printf() with different formats to print out number in HEX, DEC, OCT

#define UPTO 17

int main(void)
{
int i ;
printf("%10s%10s%10s%10s%10s%10s\n","Dec","Oct","Hex","Dec","Oct","Hex");
printf("%60s\n","-----------------------------------------------------");
for (i=0;i<UPTO;i++){
printf("%10d%10o%10x%10d%10o%10x\n",i,i,i,i+UPTO,i+UPTO,i+UPTO);
}

return 0;
}

Convert a decimal to binary : 35 divided by 2 remains 1 left 17 divided by 2 remains 1 left 8 divided by 2 remains 0 left 4 divided by 2 remains 0 left 2 divided by 2 remains 0 left 1 divided by 2 remains 1 Collect the binary bottom up side : 100011

FAQ:

Any questions or answers please help me

SOURCE CODE ( OR USEFULL FUNCTIONS):

  1. Set screen mode:

    2. One way to accomplish this is:

    union REGS inout;

    #ifdef __WATCOMC__

    inout.w.ax = 0x0013; //Mode 13h or 320x200,256 colors

    int386(0x10,&inout,&inout);

    #else

    inout.x.ax = 0x0013;

    int86(0x10,&inout,&inout);

    #endif

    After that you can access directly to screen by:

    unsigned far char *screen = (unsigned far char *)0x0A000000

  2. Scan a file:
    3. You can either use the directives(prog <  > data.dat) or open the file :
    int main(void)
   {
   char temp;
   while ((temp=getchar())!=EOF){
    do something..
    }
   return 0;
   }
or open file:

#include 
#include 

int main(int agrc,char *agrv[])
{
FILE *fp;
char filename[] ,temp;
if (argc>1){ //There are parameters
 filename = argv[x];//x is where you type filename
 fp=fopen(filename,"rb")//"r" for readonly "w" for write..
 while ((temp=fgetc(fp))!=EOF){
  do something...
 }
else
 Printf("Usage:prog param1\n");
}
return 0;//You can put return 1;for error in the print Usage
}
  3. Binary conversion ( Please refer to basic knowledge on mathematic):
    4. 
void DecToBin(int number,char bin[],char f_char)
{
int cnt=IBSIZE,remain,num=number;
do{
remain=num%2;
if (remain==1)
 bin[cnt]='1';
else
  bin[cnt]='0';
num/=2;
cnt--;
}while (num>0);
while (cnt>=0){
bin[cnt]=f_char;
cnt--;
}
bin[BITS-1]='\0';
}