Gauss Elimination problem solution in C language simple

Gauss_Elimination.c

/**
Gauss Elimination problem solution in C language [Basic]
@author : Maniruzzaman Akash
**/

#include<stdio.h>
int main(){
    int i, j, k, n;
    float matrix[100][100];
    float sum = 0.0;
    float x[100];       //Keep the values in it
    float temp = 0.0;

    printf("Please enter the order of the matrix : ");
    scanf("%d", &n);

    //Take the matrix value from the scan
    for(i = 1; i <= n; i++){
        for(j = 1; j <= n+1; j++){
            printf("Enter Matrix value for Mat[%d][%d] :", i, j);
            scanf("%f", &matrix[i][j]);
        }
    }

    printf("\n");
    //Show the matrix entered by the user
    for(i = 1; i <= n; i++){
        for(j = 1; j <= n; j++){
            printf("%f ", matrix[i][j]);
        }
        printf("\n");
    }

    //Make an upper triangular matrix first
    for(j = 1; j <= n; j++){
        for(i = 1; i <= n; i++){
            if(i > j){
                temp = matrix[i][j] / matrix[j][j];
                for(k = 1; k <= n + 1; k++){
                    matrix[i][k] = matrix[i][k] - temp * matrix[j][k];
                }
            }
        }
    }
   x[n]= matrix[n][n+1] / matrix[n][n];


    //Backward substitution
    for(i=n-1; i>=1; i--){
        sum = 0;
        for(j = i+1; j <= n; j++)
        {
            sum = sum+matrix[i][j]*x[j];
        }
        x[i]=(matrix[i][n+1]-sum) / matrix[i][i];
    }


    printf("The values are : \n");
    for(i=1; i<=n; i++)
    {
        printf("\nx%d=%f\t",i,x[i]);
    }

    return 0;
}