program to perform fundamental string functions in c
///fundamental string operation, lenth, concatenation, compare and copy strings without string.h
#include <stdio.h>
#include <stdlib.h>
int find_length(char string[]) {
int len = 0, i;
for (i = 0; string[i] != '\0'; i++) {
len++;
}
return len;
}
void join_strings(char string1[], char string2[]) {
int i, len1, len2;
len1 = find_length(string1);
len2 = find_length(string2);
for (i = len1; i < len1 + len2; i++) {
string1[i] = string2[i - len1];
}
string1[i] = '\0'; //adding null character at the end of input
}
/*returns 0 if thery are same otherwise returns 1*/
int compare_strings(char string1[], char string2[]) {
int len1, len2, i, count = 0;
len1 = find_length(string1);
len2 = find_length(string2);
if (len1 != len2)
return 1;
for (i = 0; i < len1; i++) {
if (string1[i] == string2[i])
count++;
}
if (count == len1)
return 0;
return 1;
}
void copy_string(char destination[], char source[]) {
int len, i;
len = find_length(source);
for (i = 0; i < len; i++) {
destination[i] = source[i];
}
destination[i] = '\0';
}
int main() {
char string1[20], string2[20]; //string variables declaration with size 20
int choice;
while (1) {
printf("\n1. Find Length \n2. Concatenate \n3. Compare \n4. Copy \n5. Exit\n");
printf("Enter your choice: ");
scanf("%d", & choice);
switch (choice) {
case 1:
printf("Enter the string: ");
scanf("%s", string1);
printf("The length of string is %d", find_length(string1));
break;
case 2:
printf("Enter two strings: ");
scanf("%s%s", string1, string2);
join_strings(string1, string2);
printf("The concatenated string is %s", string1);
break;
case 3:
printf("Enter two strings: ");
scanf("%s%s", string1, string2);
if (compare_strings(string1, string2) == 0) {
printf("They are equal");
} else {
printf("They are not equal");
}
break;
case 4:
printf("Enter a string: ");
scanf("%s", string1);
printf("String1 = %s\n");
printf("After copying string1 to string 2\n");
copy_string(string2, string1);
printf("String2 = %s", string2);
break;
case 5:
exit(0);
}
}
return 0;
}