For checking the size of string you can use sizeof operator. In C language their is no such thing called string but you can treat character array as a string.
Program :
#include<stdio.h>
int main(){
char *a = "America"; // Here, a is character pointer
char b[] = "German"; // Here, b is character array
printf("size of a = %ld\n",sizeof(a));
printf("size of b = %ld\n",sizeof(b));
}
Output :
size of a = 8
size of b = 7
Link : Code
Note : Here extra 1 size due to NULL '\0' and size of operator never evaluates the result it just gives the sizeof the result.