This C program has an array already saved in the source and it displays it; then requests a number from user, if the input number matches with any one in that array, it returns the position of that number in the array; otherwise, says that it is not in the array;

linearsearch.c

#include <stdio.h>

int main() {
    int data[11] = {10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60};
    int entry, i, position=1;
    printf("Here is the array:\n");
    for (i=0; i<11; i++){
        printf("%d\t", data[i]);
    }
    printf("\n");
    printf("Enter your number which you want to know about:\n");
    scanf("%d", &entry);
    for (i=0; i<11; i++){        
        if (entry == data[i]){
            printf("The position of your number in that array is: %d\n", position);
            break;
        } else {
            position++;
            if (position > 11) {
                printf("Seems like the number you entered is not in the array\n");
                break;
            }
        }
    }    
}