Simple GUI calculator
I first created a simple GUI for the calculator
to perform +-*/.
to perform +-*/.
When the user click the button the function arithmetic is called.
.
function calculator
figure('Position',[200 200 220 200],'Name','Calculator','NumberTitle','off','MenuBar','None','Resize','off');
txt=uicontrol('Style','Text','Position',[10 165 200 30],'String','0');
global stack value top op tops opstack num1 num2 flag;
flag=0;
x=10;
y=130;
top=1;
tops=1;
name=['7','8','9','/','4','5','6','*','1','2','3','-','0','+','C','='];%k
for k=1:size(name,2)
uicontrol('Style','Pushbutton','Position',[x y 50 30],'String' ,name(k),'Callback',@arithmetic) ;
x=x+50;
if(mod(k,4)==0)
x=10;y=y-35;
end
end
The String value of the pressed button is obtained using the get(object,’String’) function.
If the value is a number then it is placed in a stack.
If the value is a operator then the operator will be placed in the operator stack (opstack).
If the value is ‘C’ then the stacks top is set to 1.
function arithmetic(object,~)
num=str2double(get(object,'String'));
if((num>=0)&&(num<=9))
value=num;
evaluate();
else
op=get(object,'String');
if(op=='C')
top=1;
tops=1;
set(txt,'String','0');
else
operator();
end
end
end
The function evaluate is called to add the number to the stack.
If the stack (1) =0 and the stack (2) =9, then the stack (1) =9.
This is because, when the user enters zero and then 1, the stack value will be ‘01’. To obtain the correct value, it is better to remove the zero and display as ‘1’.
If the user enters numbers continuously without entering an operator then the values should be concatenated at each time.
For example, if the user enter 2, 4, 5 and then +, the values 245 should be displayed as a single number.
function evaluate()
stack(top)=value;
if((stack(1)==0)&&(top==2))
stack(1)=stack(top);
top=top-1;
end
str=num2str(stack(1));
for i=2:top
str=strcat(str,num2str(stack(i)));
end
top=top+1;
set(txt,'String',' ');
set(txt,'String',str);
flag=0;
end
If the user enter an operator then the operator will be added to the operator stack and the first number to perform the arithmetic operation is stored in the variable ‘num1’.
If the user enters an operator again then the operator will be added to the stack and the second number will be stored in the variable ‘num2’.
After getting the two numbers, the corresponding arithmetic operation is done based on the operator in the opstack(1).
The result will be stored in the variable ‘num1’.
function operator()
if((top~=1)||(flag==1))
opstack(tops)=op;
tops=tops+1;
if((tops==2)&&(flag~=1))
str=num2str(stack(1));
for i=2:top-1
str=strcat(str,num2str(stack(i)));
end
num1=str2double(str);
flag=1;
top=1;
elseif(tops>=3)
if(flag==0)
str=num2str(stack(1));
for i=2:top-1
str=strcat(str,num2str(stack(i)));
end
num2=str2double(str);
top=1;
if(opstack(tops-1)=='=')
calculate();
set(txt,'String',' ');
set(txt,'String',num2str(num1));
flag=1;
tops=1;
else
calculate();
set(txt,'String',' ');
set(txt,'String',num2str(num1));
flag=1;
tmp=opstack(tops-1);
opstack(1)=tmp;
tops=tops-1;
end
else
tmp=opstack(tops-1);
opstack(1)=tmp;
tops=tops-1;
end
end
end
end
function calculate()
switch (opstack(1))
case '+'
num1=num1+num2;
case '-'
num1=num1-num2;
case '/'
num1=num1/num2;
case '*'
num1=num1*num2;
end
end
end
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