#include <stdio.h>
int main()
{
char s1[100], s2[100], i;
printf("Enter string s1: ");
scanf("%s",s1);
for(i = 0; s1[i] != '\0'; ++i)
{
s2[i] = s1[i];
}
s2[i] = '\0';
printf("String s2: %s", s2);
return 0;
}

Output

Enter String s1: program
String s2: program

This above program copies the content of string s1 to string s2 manually.

C program to copy a string without using strcpy() the function:

#include <stdio.h>

int main() {
    char str1[100], str2[100];
    int i;

    printf("Enter a string:\n");
    gets(str1);

    for (i = 0; str1[i] != '\0'; i++) {
        str2[i] = str1[i];
    }

    str2[i] = '\0';

    printf("Copied string: %s\n", str2);

    return 0;
}

Explanation:

• #include <stdio.h> includes the standard input-output header file in our program.
• char str1[100], str2[100]; declares two character arrays str1 and str2 to store the original and copied strings respectively.
• int i; declares an integer variable i.
• The printf() statement is used to display a message to the user to input a string and the gets() function is used to input the string.
• The for loop starting from for (i = 0; str1[i] != '\0'; i++) copies each character of the string str1 to str2 one by one until the end of the string is reached.
• The statement str2[i] = '\0'; adds the null character at the end of the copied string to indicate the end of the string.
• The last printf() statement displays the copied string.

When we compile and run this program, it will prompt the user to input a string and then copy it without using the strcpy() function. Finally, it will display the copied string.