C Programming Code Examples C > Beginners Lab Assignments Code Examples C Program to Check String is Palindrome using Stack C Program to Check String is Palindrome using Stack This is a C Program to identify whether the string is palindrome or not using stack. - Take a string as input. - Store the string in the stack array. - Check whether the string is palindrome or not. #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX 50 int top = -1, front = 0; int stack[MAX]; void push(char); void pop(); void main() { int j, choice; char s[MAX], b; while (1) { printf("1-enter string\n2-exit\n"); printf("enter your choice\n"); scanf("%d", &choice); switch (choice) { case 1: printf("Enter the String\n"); scanf("%s", s); for (j = 0;s[j] != '\0';j++) { b = s[j]; push(b); } for (j = 0;j < (strlen(s) / 2);j++) { if (stack[top] == stack[front]) { pop(); front++; } else { printf("%s is not a palindrome\n", s); break; } } if ((strlen(s) / 2) = = front) printf("%s is palindrome\n", s); front = 0; top = -1; break; case 2: exit(0); default: printf("enter correct choice\n"); } } } /* to push a character into stack */ void push(char a) { top++; stack[top] = a; } /* to delete an element in stack */ void pop() { top--; } - Take a string as input and store it in the array s[]. - Load each character of the array s[] into the array stack[]. - Use variables front and top to represent the last and top element of the array stack[]. - Using for loop compare the top and last element of the array stack[]. If they are equal, then delete the top element, increment the variable front by 1 and compare again. - If they are not equal, then print the output as "It is not a palindrome". - Compare the elements in the steps 4-5 upto the middle element of the array stack[]. - If every characters of the array is equal, then it is a paliandrome.
