Gauss Elimination in Matlab

function [x] = g1(A, b)
%work out the number of equations
N = length(b)
%Gaussian elimination
for column=1:(N-1)
%work on all the rows below the diagonal element
for row = (column+1):N
%work out the value of d
d = A(row,column)/A(column,column);
%do the row operation
A(row,:) = A(row,:)-d*A(column,:)
b(row) = b(row)-d*b(column)
end%loop through rows
end %loop through columns
for row=N:-1:1
x(row) = b(row);
for i=(row+1):N
x(row) = x(row)-A(row,i)*x(i);
end
x(row) = x(row)/A(row,row);
end
return

Monte Carlo Simulation

N=input('enter no of dats');
r=4;
c=0;
for i=1:N
    x=r*rand(1);
    y=r*rand(1);
    if((x^2+y^2)<=r^2)
        c=c+1;
       
    end;
end;
n=c;
pi=(4*n)/N

Script For inverse of a matrix in Matlab

x=input('Enter a matrix 3*3')
y=input('Enter another 3*3 matrix')
s=x+y
 det=s(1,1)*(s(2,2)*s(3,3)-s(2,3)*s(3,2))-s(1,2)*(s(2,1)*s(3,3)-s(3,1)*s(2,3))+s(1,3)*(s(2,1)*s(3,2)-s(3,1)*s(2,2))
adj=[[(s(2,2)*s(3,3)-s(3,2)*s(2,3));-(s(2,1)*s(3,3)-s(3,1)*s(2,3));(s(2,1)*s(3,2)-s(3,1)*s(2,2))] [-(s(1,2)*s(3,3)-s(3,2)*s(1,3));(s(1,1)*s(3,3)-s(3,1)*s(1,3));-(s(1,1)*s(3,2)-s(3,1)*s(1,2))] [(s(2,2)*s(1,3)-s(1,2)*s(2,3));-(s(1,1)*s(2,3)-s(2,1)*s(1,3));(s(1,1)*s(2,2)-s(2,1)*s(1,2))]]
inverse=(1./det).*adj

Symbol Table Creation

To generate tokens

%%

{letter}({letter}|{digit})*       printf(“id: %s\n”, yytext);

%%

--------------------

1.

%{

#include<string.h>

%}

%%

(int|float|double|long|short|return|include|char) { printf("\n< Keyword,%s >",yytext);func(yytext,"Keyword");}

[\"] { printf("\n< Operator,%s >",yytext);func(yytext,"Operator"); }

['"'][\\a-zA-Z0-9|' ']+['"'] { printf("\n< id,%s >",yytext); func(yytext,"String");}

\+\+ { printf("\n< %s >",yytext);func(yytext,"Operator"); }

\-\- { printf("\n< %s >",yytext); func(yytext,"Operator");}

\=\= { printf("\n< %s >",yytext); func(yytext,"Operator");}

\!\= { printf("\n< %s >",yytext); func(yytext,"Operator");}

\+\= { printf("\n< %s >",yytext); func(yytext,"Operator");}

\-\= { printf("\n< %s >",yytext); func(yytext,"Operator");}

[/|'.']+ { printf("\n< %s >",yytext); func(yytext,"Operator");}

(printf|scanf) { printf("\n< function,%s >",yytext);func(yytext,"Function");}

[0-99]+ { printf("\n<Number,%s >",yytext);func(yytext,"Number"); }

[a-zA-Z|_][0-99|a-zA-Z|_]* { printf("\n< variable,%s>",yytext); func(yytext,"variable");}

['+'|\-|'='|':'|'%'|'&'|'('|')'|'{'|'}'|','|'#'|'!'|'@'|'$'|'*'|'<'|'>'|'?'] { printf("\n< %s >",yytext);func(yytext,"Operator");}

[';']+ { printf("\n< %s >",yytext);func(yytext,"Operator");}

\n func2();

%%

struct entry

{

char name[10];

char token[10];

}st[10];

int i=0;

func(char n[10],char t[10])

{

int j,flag=0;

for(j=0;j<i;j++)

{

if(strcmp(n,st[j].name)==0)

flag=1;

}

if(flag==0)

{

strcpy(st[i].name,n);

strcpy(st[i].token,t);

i++;

}

}

func2()

{

int k;

printf("\n===========Symbol Table==================\n");

for(k=0;k<=i;k++)

printf("%s   %s\n",st[k].name,st[k].token);

}