Two ways we can convert a string to lower case string as follows:

• using strlwr() library function from string.h

• using tolower() function by converting each charcater to lowercase

• using an iterative approach by converting each upper case character to lower case using ASCII values

1. Using strlwr() library function: this library function is not defined in C standard library and use of this function is compiler dependent. To use this we need to include string.h header file.

#include <stdio.h>

#include <string.h>

int main()

{

char info[]="Learn Programming";

strlwr(info);

printf("%s",info);

return 0;

}

2. Using tolower() library function: tolower() function is defined in ctype.h header file.This function accept one character and returns it lower case version.

#include <stdio.h>

#include <ctype.h>

int main()

{

char info[]="Learn Programming";

int i = 0;

while(info[i]!='\0'){

info[i] = tolower(info[i]);

i++;

}

printf("%s",info);

return 0;

}

3. Using ASCII values: In this approach, the ASCII values of all characters are checked. If any ASCII value is in between 65 and 90 then 32 is added and saved with that character.

#include <stdio.h>

int main()

{

char info[] = "Learn ProgrammiG";

int i = 0;

while(info[i]!='\0'){

if( info[i]>=65 && info[i]<=90)

info[i] = info[i]+32;

i++;

}

printf("The string after lowercase convertion:: %s",info);

return 0;

}