Engineering Mechanics: C and Octave Programming

151-xxx Programming Mechanical Engineer

โดย ผศ.สราวุฎฐ์ วรสุมันต์ , ประยุทธ พันธุลาภ

Heat Transfer

Thermal conductivity of some selected gases, insulation products, aluminum, asphalt, brass, copper, steel and other common materials

Viscosity of Water

Advance Topics

Numerical solutions with GNU OCTAVE

Octave and C compiler on-line

Click here to run -> rextester.com

Loop Flow Chart

ข้อสอบ กว

%Example 1

t = 0:0.1:6.3;
plot (t, cos(t), "-;cos(t);", t, sin(t*0.5), "-b;sin(t);");
print -dpng some_name.png;


%Example 2
x=1:0.1:10;
plot(x, sin(x));
print -dpng some_name.png;


%Example 3
A = [3,12; 4,2;]
C = [15; 6;]
x = inv(A)*C

%Example 4 Hydro static
rho = 1000 %kg/cu.m.
g = 9.81 %m/s2

h = 20 %m

p = rho * g * h %N/sq.m

ข้อสอบ กว

Example 05


%*****Reaction at simple beam

printf("Student No.2\n")
printf("**************\n")

F1 = 150  %KN
L = 6 %m
L1 = 1 %m  
L2 = L - L1
A = [1,1; L, 0;]
F = [F1; (L2*F1);]

R = inv(A)*F

printf("R1 = %6.3f\n",R(1))
printf("R2 = %6.3f\n",R(2))

Example 06


%****Cantiliver Beam

printf("Student No.1\n")
printf("**************\n")

F1 = 300  %KN
L = 2 %m
A = [1,0; 0, 1;]
F = [F1; (L*F1);]

R = inv(A)*F

printf("RY = %6.3f  KN\n",R(1))
printf("MA = %6.3f  KN.m\n",R(2))

Example 07

-->


%*****Reaction at simple beam F1 F2

printf("Student No.2\n")
printf("**************\n")

F1 = 100  %KN
F2 = 50 %KN
L = 6 %m
L1 = 1 %m  
L2 = 1.2 %m
FT = F1 + F2   %total force
MT = (L1*F1) + ((L1+L2)*F2)   %total moment
A = [1,1; 0, L;]
F = [FT; MT;]

R = inv(A)*F

printf("R1 = %6.3f\n",R(1))
printf("R2 = %6.3f\n",R(2))

Example 08


%*****Reaction at Cantilever Beam F1 F2

printf("Student No.2\n")
printf("**************\n")

F1 = 100  %KN
F2 = 50 %KN
L = 6 %m
L1 = 1 %m  

FT = F1 + F2   %total force
MT = (L*F1) + (L1*F2)   %total moment
A = [1,0; 0,1;]
F = [FT; MT;]

R = inv(A)*F

printf("RY = %6.3f\n",R(1))
printf("MA = %6.3f\n",R(2))

Example 09
%****Ex 9. Solve Matrix


printf("Student No.2\n")
printf("**************\n")
printf("**Solve Matrix***\n")
printf("**************\n")

A = [
-4, -11, 5, -5;
-11, -8, 10, -9;
-5, -5, 8, -7;
-2, -3, 8, -4;
]
F = [
-165;
-258;
-149;
-69;
]
disp "***********************"

R = inv(A)*F

printf("a = %6.3f \n",R(1))
printf("b = %6.3f \n",R(2))
printf("c = %6.3f \n",R(3))
printf("d = %6.3f \n",R(4))


#include <stdio.h>

int main()
{
    int number;
   
    printf("Enter an integer: ");  
    
    // reads and stores input
    scanf("%d", &number);
    // displays output
    printf("You entered: %d", number);
    
    return 0;
}

-โครงสร้างของคอมพิวเตอร์ ->Link
-ประวัติความเป็นมาของคอมพิวเตอร์ ->Link1| ->Link2
-หลักการทำงานเบื้องต้นของระบบคอมพิวเตอร์ ->Link
->Bill Gates
->Link2

พื้นฐานการเขียนโปรแกรมคอมพิวเตอร์
(Programming Fundamentals)

Programming Fundamentals

การเขียนโปรแกรมคอมพิวเตอร์ C

Link->ข้อสอบ Computer Programming

https://www.onlinegdb.com/online_c_compiler

*****Open C Online*****

***C Examples***

Android Text Editor for Copy/Paste codes

Link-> Play Store Editor

C Keywords

***Link->C Keywords***

ความแตกต่างระหว่าง Error กับ Warning

Error
>Link->First BUG
Warning

การใช้ Comment

// นำหน้า หมายถึง compiler จะไม่สนใจตั้งแต่ // จนสิ้นสุดบรรทัดนั้น
/* */ คลุม หมายถึง compiler จะไม่สนใจตั้งแต่ /* จนถึง */

Link->Data Types

Link->C-input-output
Link->C-String


/* Example 1 */


#include <stdio.h>

int main()
{
    printf ("Hello world!");
    
    return 0;
}


/* Example 2 */


    #include <stdio.h>
    int main() {   
        int number;
       
        printf("Enter an integer: ");  
        
        // reads and stores input
        scanf("%d", &number);
        // displays output
        printf("You entered: %d", number);
        
        return 0;
    }

295

296

เอกสารประกอบการสอน if else, while, do while

*****Link->PDF*****

Relational Operator

Home Work#2



#include <stdio.h>
#include <string.h>

int main()
{
    int i, found = 0;
	char size[6]; //inch
	char sv[20];
	float dia = 0; //m.
	float r = 0; //m.
	float flow = 0; //cu.m./s
	float v = 2; // m/s
 
    char pipe_size[5][20] = {
                                  "1","2","3","4","6"
                              }, name[10];
 
     char pipe_diam[5][20] = {
                                  "28.0","51.4", "76.2", "97.8", "141.6"
                              }, data[10];

    printf("Enter Size [inch]: ");
    scanf("%s",size);
    
    printf("Enter Velocity [m/s]: ");
    scanf("%s",sv);
    
    for(i = 0; i < 5; i++)
    {
        if(strcmp(size, pipe_size[i]) == 0 )
        {
            found = 1;
			//printf("data = %s" ,pipe_diam[i] );
			sscanf(pipe_diam[i] , "%f", &dia); //convert string to float
			sscanf(sv , "%f", &v); //convert string to float
			r = (dia * 0.5) / 1000.0; //mm
			flow = v * (3.14159 * r * r) * 1000; //liter/s
			printf("flow [liter/s] = %f" , flow);
            break; //out of for loop
        }
    }
 
    return 0;
}

Home Work#1


#include <stdio.h>
int main()
{
    int cpucore = 8;
    int camera = 3;
    int ram = 64;
	
    
    if (camera<2)
    {
        printf("Camera NOT Pass\n");
    }

    else
    {
        printf("Camera Pass\n");
    }
    
    if (cpucore>4)
    {
        printf("CPU CORE Pass\n");
    }

    else
    {
        printf("CPU CORE NOT pass\n");
    }
	
	
    if (ram>32)
    {
        printf("RAM Pass\n");
    }

    else
    {
        printf("RAM NOT pass\n");
    }	

    return 0;
}

การใช้ if else



//***Example if 1***


#include <stdio.h>
int main()
{
    int x = 20;
    int y = 22;
    if (x<y)
    {
        printf("Variable x is less than y");
    }
    return 0;
}



//***Example if else***


#include <stdio.h>
int main()
{
    int x = 20;
    int y = 22;
    if (x<y)
    {
        printf("Variable x is less than y");
    }

    else
    {
        printf("Variable x is NOT less than y");
    }

    return 0;
}

การใช้ for loop


#include <stdio.h>


int main()
{
    int age = 18;
    int height = 155;
    int weight = 42;
    
    if (height<=150)
    {
        printf("height NOT Pass\n");
    }

    else
    {
        printf("height Pass\n");
    }
    
    if (age<=20)
    {
        printf("age Pass\n");
    }

    else
    {
        printf("age NOT pass\n");
    }
    
    if (weight<=80)
    {
        printf("weight Pass\n");
    }

    else
    {
        printf("weight NOT pass\n");
    }

    return 0;
}


//***Example Loop 1***


#include <stdio.h>
 
int main () {

   int a;
   int b;
	b = 1;
   /* for loop execution */
   for( a = 5; a > 0; a = a - 1 ){
        b = b + 2;            
      printf("value of a: %d   b: %d\n ", a ,b);
      //printf("value of b: %d\n", b);
   }
 
   return 0;
}


//***Example for loop sum***

#include <stdio.h>
int main()
{
   int i;
   int sum;
   sum = 0;

   for (i=1; i<=3; i++)
   {
        sum = sum + i;
       printf("%d\n", sum);
   }
   return 0;
}


//***Example for loop average***

#include <stdio.h>
int main()
{   
   int i;   
   float sum;   
   float avg;   
   sum = 0;  
   for (i=1; i<=6; i++)   
   {        
      sum = sum + i;      
      printf("i=%d , sum=%f\n", i,sum);   
    }   
    printf("i=%d \n",i);   
    //reduce i by 1   
    i = i - 1;   
    printf("***i=%d*** \n",i);
    avg = sum / (float)i;   
    printf("%6.3f\n", avg);   
    return 0;
}



//***Example for loop array***


#include <stdio.h>
 
int main () {

   int n[4][4]; /* n is an array of 3X3 integers */
   int i,j;
    for ( i = 0; i < 4; i++ ) {
        for ( j = 0; j < 4; j++ ) {
            n[j][i] = i; /* set element at location n[j][i] = i */
            printf("n[%d][%d] = %d\n", i,j,n[j][i]);
        }    
   }
   
   return 0;
}

การใช้ while loop


//***Example While Loop 1***


#include <stdio.h>
int main()
{
   int count=1;
   while (count <= 4)
   {
	printf("%d ", count);
	count++;
   }
   return 0;
}



//***Example While Loop 2***


#include <stdio.h>
int main()
{
   int x;
   int y;
   x = 5;
   y = 2;

   while (x > 0)
   {
        x = x - 1;
        y = y * x;
	printf("y = %d \n ", y);
   }
   return 0;
}


//***Example While Loop 3***


#include <stdio.h>
int main()
{
   int i;
   int j;
   i = 1;
   j = 0;

   for ( i = 1; i <= 4; i++ ) {
       if ((i-1)/2 == 0) 
       {
	 printf("i = %d \n ", i);
         j = i +1;
       }
   }
   return 0;
}

การใช้ do while loop


//***Example Do While Loop 1***

#include <stdio.h>
int main()
{
	int j=0;
	do
	{
		printf("Value of variable j is: %d\n", j);
		j++;
	}while (j<=3);
	return 0;
}

/* Example 3.1 */



#include <stdio.h>     
int main() {
  short a;
  long b;
  long long c;
  long double d;
  printf("size of short = %d bytes\n", sizeof(a));
  printf("size of long = %d bytes\n", sizeof(b));
  printf("size of long long = %d bytes\n", sizeof(c));
  printf("size of long double= %d bytes\n", sizeof(d));
  return 0;
}




/* Example 3.2 */

#include <stdio.h>     
int main() {
  short a;
  long b;
  long long c;
  long double d;
  printf("size of short = %d bytes\n", (int)sizeof(a));
  printf("size of long = %d bytes\n", (int)sizeof(b));
  printf("size of long long = %d bytes\n", (int)sizeof(c));
  printf("size of long double= %d bytes\n", (int)sizeof(d));
  return 0;
}



/* Example 4 */


#include <stdio.h> 
int main(){
    char chr = 'a';    
    printf("character = %c.", chr);  
    return 0;
} 



/* Example 5 */



#include <stdio.h>


int main() {

char first[100], last[100];

	int i;

	printf("nEnter your first name:");

	scanf("%s", first );

	printf("nEnter your last name:");

	scanf("%s", last );

	printf("nYour full name is: %s %sn", first, last );

	printf("First name is: ");

	for( i=0; i<100; i++ ){
        if ((first[i] > 32) && (first[i] < 123)){
	        printf("%c ",first[i]);
        }

	}

	printf("nLast name is: ");

	for( i=0; i<100; i++ ){

	   printf("%c ",last[i]);

	}

	printf("n");

    return 0;
}

การเขียนโปรแกรมคอมพิวเตอร์ Octave

https://octave-online.net/

*****Open Octave Online*****

Run Octave
หน้าจอของโปรแกรม Octave
Command Window
Editor

Octave แก้ระบบสมการ

ระบบสมการ ->Link1


A = [1,1,1; 0,2,5; 2,5,-1;]
C = [6;-4;27;]
x = inv(A) * C
x

Introduction to Octave

#
i = 2 * 4
i

#
x = 0 : 0.1 : 1;
x

y = [ 0 : 0.1 : 1];
y

#แก้ระบบสมการ

A = [1,1,1; 0,2,5; 2,5,-1;]
C = [6;-4;27;]
x = inv(A) * C
x


######plot1###############


x = 1:5;  y = 1:5;
plot (x,y,"g");
title ("plot() of green line at 45 degrees");


######plot2###############


x = 1:5;  y = 1:5;
plot (x,y,"g*");
title ("plot() of green stars along a line at 45 degrees"); 


###### plot function 1 #########


x = -10:0.1:10;
plot (x, sin (x)); 


###### plot function 2 #########


x = -10:0.1:10;
y = sin(x);
plot (x, y); 
 

###### plot function 3 #########


x1 = 1:5;  y1 = 1:5;
x2 = 5:9; y2 = 5:-1:1;
plot (x1,y1,"bo-", x2,y2,"rs-");
axis ("tight");
title ({"plot() of blue circles ascending and red squares descending";
         "connecting lines drawn"}); 
 

###### plot function 4 #########


x = [0:10]';
y = [sin(x), cos(x)]
h = stem (x, y);
set (h(2), "color", "g");
set (h(1), "basevalue", -1)


###### Histogram 1 #########


 hist (randn (10000, 1), 30);


###### Histogram 2 #########


h = bar (rand (5, 10));
set (h(1), "basevalue", 0.5); 


###### Histogram 3 #########


h = bar (rand (10, 3));
set (h(1), "facecolor", "r")
set (h(2), "facecolor", "g")
set (h(3), "facecolor", "b") 


###### Rose Map #########


[th, r] = rose ([2*randn(1e5,1), pi + 2*randn(1e5,1)]);
polar (th, r);


###### Contour 1 #########


x = 0:2;
y = x;
z = x' * y;
contour (x, y, z, 2:3) 


###### Contour 2 #########


[x, y, z] = peaks (50);
contourf (x, y, z, -7:9)

***********************************
Sheet
*******************************************
<.p>

แก้ระบบสมการ

->Link1


A = [1,1,1; 0,2,5; 2,5,-1;]
C = [6;-4;27;]
x = inv(A) * C
x

Assignment 1/2019

***เลยกำหนดส่ง 5 ม.ค. 2563***

Sunday, September 8, 2019

C and Octave Programming

151-xxx Programming Mechanical Engineer

Heat Transfer

Viscosity of Water

Advance Topics

Octave and C compiler on-line

ข้อสอบ กว

ข้อสอบ กว

พื้นฐานการเขียนโปรแกรมคอมพิวเตอร์ (Programming Fundamentals)

การเขียนโปรแกรมคอมพิวเตอร์ C

Android Text Editor for Copy/Paste codes

C Keywords

ความแตกต่างระหว่าง Error กับ Warning

การใช้ Comment

เอกสารประกอบการสอน if else, while, do while

Relational Operator

Home Work#2

Home Work#1

การใช้ if else

การใช้ for loop

การใช้ while loop

การใช้ do while loop

การเขียนโปรแกรมคอมพิวเตอร์ Octave

Octave แก้ระบบสมการ

Introduction to Octave

แก้ระบบสมการ

Assignment 1/2019

พื้นฐานการเขียนโปรแกรมคอมพิวเตอร์
(Programming Fundamentals)