convert string to uppercase in c
For those of you who want to uppercase a string and store it in a variable (that was what I was looking for when I read these answers).
#include <stdio.h> //<-- You need this to use printf.
#include <string.h> //<-- You need this to use string and strlen() function.
#include <ctype.h> //<-- You need this to use toupper() function.
int main(void)
{
string s = "I want to cast this"; //<-- Or you can ask to the user for a string.
unsigned long int s_len = strlen(s); //<-- getting the length of 's'.
//Defining an array of the same length as 's' to, temporarily, store the case change.
char s_up[s_len];
// Iterate over the source string (i.e. s) and cast the case changing.
for (int a = 0; a < s_len; a++)
{
// Storing the change: Use the temp array while casting to uppercase.
s_up[a] = toupper(s[a]);
}
// Assign the new array to your first variable name if you want to use the same as at the beginning
s = s_up;
printf("%s \n", s_up); //<-- If you want to see the change made.
}
//If you want to lowercase a string instead, change toupper(s[a]) to tolower(s[a]).