Gauss Elimination method for solving n-linear equations in C language

This is a simple C language program that calculates solution of n-linear equations using Non-pivotal Gauss Elimination method. It uses upper triangular matrix to do so, for solution using lower triangular matrix visit here.

#include<stdio.h>
#include<conio.h>
 
float matrix[10][10], m, temp[10];
int i, j, k, n;
 
void upper_triangularization() {
	for (i=0; i<n-1; i++)
		for (j=i+1; j<n; j++) {
			m	= matrix[j][i]/matrix[i][i];
			for (k=0; k<n+1; k++) {
				matrix[j][k]	= matrix[j][k]-(m*matrix[i][k]);
			}
		}
} //upper_traingulisation
 
void back_subsitution() {
	for (i=n-1; i>=0; i--) {
		m	= matrix[i][n];
		for (j=n-1; j>i; j--)
			m	= m - temp[n-j] * matrix[i][j];
		temp[n-i]	= m/matrix[i][i];
		printf("\n x%d => %f", i+1, temp[n-i]);
	}
} // back_subsitution
 
void main() {
	printf("Enter number. of variables :: ");
	scanf("%d", &n);
 
	printf("Enter the augmented matrix: \n");
	for (i=0; i<n; i++)
		for (j=0; j<n+1; j++)
			scanf("%f", &matrix[i][j]);
 
	upper_triangularization();
 
	printf("The upper traingular matrix is : \n");
 
	for (i=0; i<n; i++) {
		for (j=0; j<n+1; j++)
			printf("%f \t", matrix[i][j]);
		printf("\n");
	}
 
	printf("The required result is : \n");
 
	back_subsitution();
 
	getch();
} // main

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Abhishek Gupta

I am Abhishek from India. I have been working as a software engineer from last 6+ years, and it is my passion to learn new things and implement them as a practice.

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