Swap two strings using pointers

Posted on Apr 21, 2020

C program to swap two strings using pointers.

Program

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#define MAX 50

void swap(char *str1, char *str2)
{
    char *temp = (char *)malloc((strlen(str1) + 1) * sizeof(char));
    strcpy(temp,str1);
    strcpy(str1,str2);
    strcpy(str2,temp);
}

void main()
{
	char str1[MAX], str2[MAX], temp[MAX];

    printf("Enter first string\t:");
    gets(str1);
    printf("Enter second string\t:");
    gets(str2);

    printf("\nBefore swapping");
    printf("\nFirst string\t:%s",str1);
    printf("\nSecond string\t:%s",str2);

    swap(str1, str2);

    printf("\n\nAfter swapping");
    printf("\nFirst string\t:%s",str1);
    printf("\nSecond string\t:%s",str2);

    getch();
}

Output

Enter first string      :welcome
Enter second string     :coursecrux

Before swapping
First string    :welcome
Second string   :coursecrux

After swapping
First string    :coursecrux
Second string   :welcome