/ C Program to execute Gauss Jacobi Iteration Method

#include <stdio.h>
#include <conio.h>
#include <math.h>
#include<windows.h>

/* declaration of gotoxy function */
void gotoxy(short x, short y);                                  

/* definition of gotoxy function */
void gotoxy(short x, short y)                                                
{
 COORD pos ={x,y};
 SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), pos);
}

float f(float x,float y,float z)
{
  return ((4-2*z+y)/10);
  //x=(4-2*z+y)/10
}

float s(float x,float y,float z)
{
  return ((3-x+z)/10);
  //y=(3-x+z)/10
}

float t(float x,float y,float z)
{
  return ((7-2*x-3*y)/20);
  //z=(7-2*x-3*y)/20
}

int main()
{
  float x0,y0,z0,x1=0,y1=0,z1=0,tempx,tempy,tempz,error,e1,e2,e3;
  int iteration=0;
  printf("\t\t\tGauss Jacobi Method\n\n");
  printf("Enter Tolerable Error -> ");
  scanf("%f",&error);
  
  printf("\nEnter initial values:\n");
  printf("\nEnter First value -> ");
  scanf("%f",&x0);
  printf("Enter Second value -> ");
  scanf("%f",&y0);
  printf("Enter Third value -> ");
  scanf("%f",&z0);
  
  printf("\n******************");
/* Creating Header of the table */

printf("\nCount");
gotoxy(12,10);
printf("x");
gotoxy(28,10);
printf("y");
gotoxy(44,10);
printf("z\n");

  do
  {
    tempx=x1;
    tempy=y1;
    tempz=z1;
    
    /Putting initial values in the Equations/
    x1=f(x0,y0,z0);
    y1=s(x0,y0,z0);
    z1=t(x0,y0,z0);
    
    /* Printing the values in table */
    printf("%d\t%f\t%f\t%f\n",iteration,x1,y1,z1);
    
     /* Error */
    e1 = fabs(tempx-x1);
    e2 = fabs(tempy-y1);
    e3 = fabs(tempz-z1);


    iteration++;
    
    /* Set values for next iteration */
    x0=x1;
    y0=y1;
    z0=z1;
    
  }
  
  while(fabs(e1)>error && fabs(e2)>error && fabs(e3)>error);
  
  printf("\n\n*****************\n");
  printf("--------------------");
  printf("\nSolution:\n");
  printf("\nx=%f\ny=%f\nz=%f\n",x1,y1,z1);
  printf("Iteration=%d\n",iteration);
  printf("--------------------");
  getch();
}

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About C++

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  • Supports different platforms like Windows, various Linux flavours, MacOS etc
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Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}