[c] C - Convert an uppercase letter to lowercase

A really simple program. I just want to turn an 'A' into an 'a', but output is giving me 'A'.

#include <stdio.h>

int main(void) {
    putchar(lower('A')); 

}

lower(a) 
int a; 
{
    if ((a >= 65) && (a >= 90))
        a = a + 32; 
    return a;  
}

Use This code

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
void main(){
char a[10];
clrscr();
gets(a);
int i,length=0;
for(i=0;a[i]!='\0';i++)
length+=1;
for(i=0;i<length;i++){
a[i]=a[i]^32;
}
printf("%s",&a);
getch();
}

In ASCII the upper and lower case alphabet are 0x20 apart from each other, so this is another way to do it.

int lower(int a) 
{
    if ((a >= 0x41) && (a <= 0x5A))
        a |= 0x20; 
    return a;  
}

#include<stdio.h>

void main()
{
 char a;

 clrscr();
 printf("enter a character:");
 scanf("%c",&a);

 if(a>=65&&a<=90)
   printf("%c",a+32);
 else
   printf("type a capital letter");

 getch();
}

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

int main()
{
    char string[] = "Strlwr in C";

    printf("%s\n",strlwr(string));

    return  0;
}

use strlwr for lowering the case

One way to make sure it is correct is by using character instead of ascii code.

if ((a >= 65) && (a <= 90))

what you want is to lower a case. it's better to use something like if (a >= 'A' && a <= 'Z') . You don't have to remind all ascii code :)

If condition is wrong. Also return type for lower is needed.

#include <stdio.h>

int lower(int a)  
{
    if ((a >= 65) && (a <= 90))
        a = a + 32; 
    return a;  
}

int _tmain(int argc, _TCHAR* argv[])
{

    putchar(lower('A')); 
    return 0;
}

I believe you want <= 90

lower(a) 
int a; 
{
    if ((a >= 65) && (a <= 90))
        a = a + 32; 
    return a;  
}

Although tolower would probably just save you the hassle unless you wanted to do this yourself. http://www.cplusplus.com/reference/cctype/tolower/

You can convert a character from lower case to upper case and vice-versa using bit manipulation as shown below:

#include<stdio.h>
int main(){
  char c;
  printf("Enter a character in uppercase\n");
  scanf("%c",&c);
  c|=' '; // perform or operation on c and ' '
  printf("The lower case of %c is \n",c);
  c&='_'; // perform 'and' operation with '_' to get upper case letter. 
  printf("Back to upper case %c\n",c);   
  return 0;
}

In ASCII the upper and lower case alphabet is 0x20 (in ASCII 0x20 is space ' ') apart from each other, so this is another way to do it.

int lower(int a) 
{
    return a | ' ';  
}