Building a simple fitness calculator. We are very new to this. Its showing me several errors. Please help

Hello Everyone,

Several errors are being showned while designing this program. Please help me out. Hoping for a positive co-operation.

Following is this programme code :

#include<reg51.h>
void lcdcmd(unsigned char);
void lcddata(unsigned char);
void MSDelay(unsigned int);
void disp_num(float num);
int get_num(char ch);
void lcdinit();
char scan_key(void);
unsigned char s[17]={"ENTER GENDER = "};
unsigned char s1[12]={"ENTER AGE = "};
unsigned char s2[15]={"ENTER WEIGHT = "};
unsigned char s3[15]={"ENTER HEIGHT = "};
unsigned char s4[12]={"PARAMETER = "};
sfr ldata = 0xA0;
sbit rs = P3^7;
sbit rw = P3^5;
sbit en = P3^6;
sbit r0=P1^0;
sbit r1=P1^1;
sbit r2=P1^2;
sbit r3=P1^3;
sbit c0=P1^4;
sbit c1=P1^5;
sbit c2=P1^6;
sbit c3=P1^7;

void lcdinit(){
MSDelay(15000);
lcdcmd(0x30);
MSDelay(4500);
lcdcmd(0x30);
MSDelay(300);
lcdcmd(0x30);
MSDelay(600);
lcdcmd(0x38);
lcdcmd(0x0F);
lcdcmd(0x01);
lcdcmd(0x06);
lcdcmd(0x80);
}

int main (void)
{
while(1){
unsigned int k=0,m=0,n=0,l=0,p=0;double a1,w2,h3,e,b,q; char key,key1;unsigned char ch2,ch1;
lcdinit();

while(s[k]!='\0')
{
lcddata(s[k]);
k++;
}
ch1=scan_key();
lcddata(ch1);
lcdcmd(0x01);

while(s1[m]!='\0')
{
lcddata(s1[m]);
m++;
}
key=scan_key();
a1=get_num(key);
lcddata(key);
lcdcmd(0x01);

while(s2[n]!='\0')
{
lcddata(s2[n]);
n++;
}
key=scan_key();
w2=get_num(key);
lcddata(key);
lcdcmd(0x01);

while(s3[l]!='\0')
{
lcddata(s3[l]);
l++;
}
key1=scan_key();
h3=get_num(key1);
lcddata(key1);
lcdcmd(0x01);

while(s4[p]!='\0')
{
lcddata(s4[p]);
p++;
}
ch2=scan_key();
lcddata(ch2);
lcdcmd(0x01);
switch(ch2)

{
case '+':
disp_num(w2/h3*h3);
break;

case '-':
e = 10*w2+6.25*h3-5*a1+5
disp_num(e);
break;

case '*':
b = 1.20*(w2/h3*h3)+0.23*a1-16.2
disp_num(b);
break;

case '/':
q = 0.407*w2+0.267*h3-19.2
disp_num(q);
break;
}
return 0;
}
}
void lcdcmd(unsigned char value)
{
ldata = value;
rs = 0;
rw = 0;
en = 1;
MSDelay(50);
en = 0;
MSDelay(50);

}
void lcddata(unsigned char value)
{
ldata = value;
rs = 1;
rw = 0;
en = 1;
MSDelay(50);
en = 0;
MSDelay(50);
}
void MSDelay(unsigned int itime)
{
unsigned int i, j;
for(i=0;i< itime;i++)
for(j=0;j<5;j++);
}
char scan_key()
{
unsigned char c;
c='s';
while(!(c=='0' && c=='1' && c=='2' && c=='3' && c=='4' && c=='5' && c=='6' && c=='7' && c=='8'
&& c=='9' && c=='+' && c=='-' && c=='#' && c=='$' && c=='*' && c=='/' ))
{
r0=0;r1=1;r2=1;r3=1;
if(c0==0 && r0==0 ){lcddata('1');MSDelay(100000);return c='1';}
if(c1==0 && r0==0){ lcddata('2');MSDelay(100000);return c= '2';}
if(c2==0 && r0==0){ lcddata('3');MSDelay(100000);return c= '3';}
if(c3==0 && r0==0){ lcddata('4');MSDelay(100000);return c= '4';}

r0=1;r1=0;r2=1;r3=1;

if(c0==0 && r1==0){ lcddata('5');MSDelay(100000);return c= '5';}
if(c1==0 && r1==0){ lcddata('6');MSDelay(100000);return c= '6';}
if(c2==0 && r1==0){ lcddata('7');MSDelay(100000);return c= '7';}
if(c3==0 && r1==0){ lcddata('8');MSDelay(100000);return c= '8';}

r0=1;r1=1;r2=0;r3=1;

if(c0==0 && r2==0){ lcddata('9');MSDelay(100000);return c= '9';}
if(c1==0 && r2==0){ lcddata('0');MSDelay(100000);return c= '0';}
if(c2==0 && r2==0){ lcddata('+');MSDelay(100000);return c= '+';}
if(c3==0 && r2==0){ lcddata('-');MSDelay(100000);return c= '-';}

r0=1;r1=1;r2=1;r3=0;

if(c0==0 && r3==0){ lcddata('*');MSDelay(100000);return c= '*';}
if(c1==0 && r3==0){ lcddata('/');MSDelay(100000);return c= '/';}
if(c2==0 && r3==0){ lcddata('^');MSDelay(100000);return c= '^';}
if(c3==0 && r3==0){ lcddata('#');MSDelay(100000);return c= '#';}
}
return 0;
}

int get_num(char ch) //convert char into int
{
switch(ch)
{
case '0': return 0; break;
case '1': return 1; break;
case '2': return 2; break;
case '3': return 3; break;
case '4': return 4; break;
case '5': return 5; break;
case '6': return 6; break;
case '7': return 7; break;
case '8': return 8; break;
case '9': return 9; break;
}
return 0;
}

void disp_num(double num) //displays number on LCD
{
unsigned char UnitDigit = 0; //It will contain unit digit of numb
unsigned char TenthDigit = 0; //It will contain 10th position digit of numb
unsigned char decimal = 0;
int j;
int numb;
j=(int)(num*10);
numb=(int)num;
if(numb<0)
{
numb = -1*numb; // Make number positive
lcddata('-'); // Display a negative sign on LCD
}

TenthDigit = (numb/10); // Findout Tenth Digit

if( TenthDigit != 0) // If it is zero, then don't display
lcddata(TenthDigit+0x30); // Make Char of TenthDigit and then display it on LCD

UnitDigit = numb - TenthDigit*10;

lcddata(UnitDigit+0x30); // Make Char of UnitDigit and then display it on LCD
lcddata('.');
decimal=(j%10)+0x30;
lcddata(decimal);
MSDelay(2000000);
}