need help in coding of micro-controller

[saba.asif]

this is my coding in which i am comparing 2 strings. coding is for micro-controller. one string is already stored in code and second string is taken by user. i don't know why but it is not comparing the strings. please someone correct my mistake in the coding.

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Code C - [expand]
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#include<reg51.h>
#include<string.h>
#define all_on P2=0x0f            
#define all_off P2=0x00
#define dataport P0
#define cmdport P1
#define output P2
 
char y;int k;
sbit rs=cmdport^0;           
sbit rw=cmdport^1;
sbit en=cmdport^2;
sbit tv=output^0;
sbit fan=output^1;
sbit light=output^2;
sbit ac=output^3;
 
char compare1[4]="4211";         //  TV ON
char compare2[4]="4212";         //  FAN ON
char compare3[4]="4213";         //  LIGHT ON
char compare4[4]="4214";         //  AC ON
char compare5[4]="4215";         //  TV OFF
char compare6[4]="4216";         //  FAN OFF
char compare7[4]="4217";         //  LIGHT OFF
char compare8[4]="4218";         //  AC OFF 
char compare9[4]="4111";         //  ALL ON 
char compare0[4]="4119";     //  ALL OFF   
char input[4];               //input string      
 
void delay(int time)
{ 
 unsigned int i,j;
 for(i=0;i<time;i++)
 for(j=0;j<1275;j++);
 }    // delay funtion
 
void lcddata(char item)
{
 dataport=item;
 rs=1,rw=0,en=1;
 delay(5),en=0;
 }            // funtion to send data to lcd
 
void print(char cmd, char *str)
{
 dataport=cmd;
 rs=0,rw=0,en=1;
 delay(5),en=0;       // funtion to send cmd and print data to lcd
 while(*str!='\0')
 {
  lcddata(*str);
  str++;
 }
 }
 
void LCD_clear()
{
 delay(50);
 print(0x01,0);
}
                                          // funtion to clear lcd
void LCD_Init()                                                                   // funtion to LCD initialize
{
 print(0x38,0);
 print(0x06,0);
 print(0x0e,0);                                       // print introduction on lcd
 print(0x80,"  A PROJECT BY  ");
 print(0xc0,"  BSEE   ");
 LCD_clear();
 print(0x80,"DTMF CONTROLLED ");
 print(0xc0,"HOME AUTOMATION ");
 LCD_clear();
 print(0x80,"  SYSTEM READY  ");
 }
 
void serial_init()
{
TMOD=0X20;
SCON=0X50;
TH1=0XFD;
TR1=1;
}                             // funtion to initialize serial communication
 
void main()                                                                       // main program 
{
 all_off;
 serial_init();
 LCD_Init();                                                  // initiaze lcd and serial communication 
while(1)
{
 print(0xC0,"ENTER CODE ");                                                       // enter a string of length 4 by using for loop
 for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  }              
 
 if(strcmp(compare1, input)==0)                                               // compare input strings with stored strings
 {
 LCD_clear();
 print(0x80,"     TV ON     ");
 tv=1;
 }  
 print(0xC0,"ENTER CODE "); 
 for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare2, input)==0)
{LCD_clear();print(0x80,"    FAN ON     ");fan=1;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare3, input)==0)
{LCD_clear();print(0x80,"   LIGHT ON    ");light=1;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare4, input)==0)
{LCD_clear();print(0x80,"     AC ON     ");ac=1;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare5, input)==0)
{LCD_clear();print(0x80,"     TV OFF    ");tv=0;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare6, input)==0)
{LCD_clear();print(0x80,"    FAN OFF    ");fan=0;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare7, input)==0)
{LCD_clear();print(0x80,"   LIGHT OFF   ");light=0;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare8, input)==0)
{LCD_clear();print(0x80,"     AC OFF    ");ac=0;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare9, input)==0)
{LCD_clear();print(0x80,"    ALL ON     ");all_on;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
 if(strcmp(compare0, input)==0)
{LCD_clear();print(0x80,"    ALL OFF    ");all_off;}
print(0xC0,"ENTER CODE ");  
for(k=0;k<4;k++)
 { 
  while(RI==0);
  y=SBUF;
  input[k]=y;
  lcddata(input[k]);
  RI=0;
  delay(40);
  } 
}
}

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[FvM]

strcmp() and similar functions are working with C strings and expect a terminating 0 character. To work with strcmp() your strings must be defined with a length of 5 bytes. Likewise a terminating 0 must be appended when reading in strings character by character.