Using inbuilt function
Using the inbuilt function strcpy() from string.h header file to copy one string to the other. strcpy() accepts a pointer to the destination array and source array as a parameter and after copying it returns a pointer to the destination string. Using %s we can print the string(%s prints the string from the base address till the null character).
Below is the implementation using the above method:
C
// C program to copy the string using // strcpy function #include <stdio.h> #include <stdlib.h> #include <string.h> // Function to copy the string char* copyString(char s[]) { char* s2; s2 = (char*)malloc(20); strcpy(s2, s); return (char*)s2; } // Driver Code int main() { char s1[20] = "GeeksforGeeks"; char* s2; // Function Call s2 = copyString(s1); printf("%s", s2); return 0; } |
GeeksforGeeks
using loops
The idea is to use a for loop to copy the content of the first array to the second array one by one.
Below is the implementation using the above method:
C
// C program to copy string using loops #include <stdio.h> #include <stdlib.h> #include <string.h> // Function to copy the string char* copyString(char s[]) { int i; char* s2; s2 = (char*)malloc(20); // Executing till null character // is found for (i = 0; s[i] != '\0'; i++) { // Copy the character one // by one from s1 to s2 s2[i] = s[i]; } // Return the pointer of newly // created string return (char*)s2; } // Driver Code int main() { char s1[20] = "GeeksforGeeks"; char* s2; // Function Call s2 = copyString(s1); printf("%s", s2); return 0; } |
GeeksforGeeks
using pointers
The idea is to copy the contents of the string array to another array using pointers and print the resultant string by traversing the new pointer.
Below is the implementation using the above method:
C
// C program to copy the string // using pointers #include <stdio.h> #include <stdlib.h> #include <string.h> // Function to copy the string char* copyString(char s[]) { char *s2, *p1, *p2; s2 = (char*)malloc(20); p1 = s; p2 = s2; // Executing till the null // character is found while (*p1 != '\0') { // Copy the content of s1 to s2 *p2 = *p1; p1++; p2++; } *p2 = '\0'; return s2; } // Driver Code int main() { char s1[20] = "GeeksforGeeks"; char* s2; s2 = copyString(s1); printf("%s", s2); return 0; } |
GeeksforGeeks
using pointers and post-increment
The idea is to use a while loop to assigns the content of string array1 to string array2 one by one and increment using post operator as it returns ASCII value so the condition will be true and it will be in the loop and transfer till the condition is false, and we will come out of the loop.
Below is the implementation using the above method:
C
// C program to copy the string #include <stdio.h> #include <stdlib.h> // Function to copy the string void copyString(char* t, char* s) { // (return ASCII value which is True, // therefore will be in the loop // till the condition is False while (*t++ = *s++) ; } // Driver Code int main() { char s2[20] = "GeeksforGeeks"; char s1[20]; // Function Call copyString(s1, s2); printf("%s", s1); return 0; } |
GeeksforGeeks
Note: In all the above methods the size of the destination array must be greater than the length of the source string to copy all the characters.
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